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Unit 3 Projects — Teacher Answer Key

Worked solutions using the default input values for both project versions. For teachers only.

Unit 3 · Ratios & Rates 6.RP.1 6.RP.2 6.RP.3 Teacher Use Only

For teachers — worked solutions using the default values. Students who change inputs get different but similarly-structured answers. Each phase shows: default inputs used, step-by-step arithmetic, the correct final answer, and the exact quick-check answer. Sample expert responses and rubric guidance are included for scoring.

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Version A — Smoothie Bar Designer

Context: Opening a school smoothie bar using ratios, equivalent ratios, unit rates, and better-buy comparisons.

1
Writing & Simplifying Ratios · 6.RP.1

Write Your Smoothie Recipe Ratio

Cups of fruit (default)
6
Cups of yogurt (default)
4
3:2
Three forms of the ratio:
• Colon form: 6:4
• Word form: 6 to 4
• Fraction form: 6/4

Simplification: GCF(6, 4) = 2. Divide both: 6 ÷ 2 = 3, 4 ÷ 2 = 2.
Simplified ratio = 3:2. For every 3 cups of fruit use 2 cups of yogurt.
Sample Expert Response (deliverable starter)

"My smoothie recipe uses 6 cups of fruit to 4 cups of yogurt. I can write this ratio as 6:4, 6 to 4, or 6/4. Since GCF(6, 4) = 2, the simplified ratio is 3:2, meaning for every 3 cups of fruit I need exactly 2 cups of yogurt to keep the same taste."

Sample 4/3/2 Rubric Guidance — Writing & Simplifying Ratios

4 (Expert): Writes all three forms correctly (6:4, 6 to 4, 6/4), identifies GCF = 2, shows the division step (6÷2, 4÷2), states the simplified ratio 3:2, and explains what it means in context ("for every 3 cups of fruit…").
3 (Proficient): All three forms correct and simplified ratio 3:2 stated; GCF work may be implicit.
2 (Developing): Ratio written but one form is missing, or simplification skipped/incorrect.

2
Equivalent Ratios & Ratio Tables · 6.RP.3

Scale Up Your Recipe

Base cups of fruit (1×)
6
Base cups of yogurt (1×)
4
3 Equivalent Ratios
Multiply both parts of the base ratio (6:4) by the batch multiplier:
Batch SizeFruit (cups)Yogurt (cups)Ratio
1× batch646:4 → 3:2
2× batch12812:8 → 3:2
3× batch181218:12 → 3:2
All three rows are equivalent ratios because each simplifies to 3:2. The recipe taste is identical at every scale.
Sample Expert Response

"To serve more smoothie customers I scaled my base recipe (6 cups fruit, 4 cups yogurt). A double batch uses 12 cups of fruit and 8 cups of yogurt, and a triple batch uses 18 cups and 12 cups. All three ratios simplify to 3:2, confirming the taste stays the same no matter how many I make."

Sample 4/3/2 Rubric Guidance — Equivalent Ratios / Ratio Table

4 (Expert): All three rows correct (6:4, 12:8, 18:12); explains why each ratio is equivalent (same GCF simplification, or "multiplied both parts by the same factor"); connects back to the recipe context.
3 (Proficient): All table rows numerically correct.
2 (Developing): One or two rows correct; pattern not explained.

3
Unit Rate & Better Buy · 6.RP.2 · 6.RP.3

Price Your Smoothies Fairly

Part A — Unit Rate

Total cost for batch
$9.00
Smoothies per batch
3
$3.00 per smoothie
Unit rate = Total cost ÷ Number of smoothies
$9.00 ÷ 3 = $3.00 per smoothie
Set the selling price above $3.00 to make a profit.

Part B — Better Buy

Pack A price
$4.50
Pack A cups
3
Pack B price
$7.20
Pack B cups
6
Pack B is the better buy
Pack A: $4.50 ÷ 3 cups = $1.50 per cup
Pack B: $7.20 ÷ 6 cups = $1.20 per cup
Pack B saves $0.30 per cup. Even though Pack B costs more upfront, its unit price is lower.
Sample Expert Response

"Each smoothie costs $3.00 to make ($9.00 ÷ 3), so I must sell each for more than $3.00 to profit. For yogurt, Pack B ($7.20 for 6 cups = $1.20/cup) beats Pack A ($4.50 for 3 cups = $1.50/cup) by $0.30 per cup, so I will order Pack B even though it costs more in total."

Sample 4/3/2 Rubric Guidance — Unit Rate & Better Buy

4 (Expert): Unit rate $3.00/smoothie correct with division shown; both unit prices computed ($1.50, $1.20), Pack B identified as better buy with a contextual explanation ("saves $0.30/cup").
3 (Proficient): Unit rate correct; better buy correctly identified.
2 (Developing): Unit rate attempted; better buy missing or incorrect (e.g., chose Pack A because the total price is lower).

4
Ratio Reasoning & Quick Check · 6.RP.1 · 6.RP.3

Menu Board Decision & Quick Check

Quick Check — Simplify the ratio 12:18
What is the simplified form of 12:18?
2:3
GCF(12, 18) = 6. Divide both: 12 ÷ 6 = 2, 18 ÷ 6 = 3. Simplified ratio = 2:3. The JS accepts exactly "2:3".
Sample Expert Response — Menu Board Reflection (Full Deliverable)

"My smoothie recipe uses a ratio of 6 cups of fruit to 4 cups of yogurt, which simplifies to 3:2. To serve more customers I can scale up to 12 cups of fruit and 8 cups of yogurt for a double batch, keeping the same 3:2 ratio. Each smoothie costs $3.00 to make (unit rate: $9.00 ÷ 3), so I priced my smoothies at $4.50 to earn a $1.50 profit each. I chose Pack B yogurt because it costs $1.20 per cup vs. Pack A's $1.50 per cup — saving $0.30 per cup. My featured menu ratio is 3:2 fruit to yogurt because the extra fruit creates a sweeter, fruitier taste that customers enjoy."

Sample 4/3/2 Rubric Guidance — Communication

4 (Expert): Reflection explicitly cites all four numeric results (ratio in three forms, scaled table values, unit rate, both better-buy unit prices) and gives a clear, reasoned choice for the menu board ratio.
3 (Proficient): Uses most numbers and gives a clear decision.
2 (Developing): Vague or missing key numbers (e.g., only mentions the ratio without citing the unit rate or better buy).


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Version B — Sports Stats Scout

Context: Junior sports analyst computing unit rates, equivalent ratios, and season projections for two players.

1
Unit Rate · 6.RP.2

Compute Each Player's Rate

Player A name (default)
Jordan
Player B name (default)
Riley
Jordan total points
84
Jordan games played
12
Riley total points
70
Riley games played
10
Jordan: 7.00 ppg  |  Riley: 7.00 ppg
Jordan: 84 pts ÷ 12 games = 7.00 points per game
Riley: 70 pts ÷ 10 games = 7.00 points per game
Both players are tied at 7.00 points per game with the default values.
Sample Expert Response

"Jordan scored 84 points in 12 games, giving a unit rate of 7.00 points per game (84 ÷ 12). Riley scored 70 points in 10 games, also 7.00 ppg (70 ÷ 10). On a per-game basis the two players are perfectly tied, so I need additional data — like the equivalent-ratio comparison and season projection — to make a recommendation."

Sample 4/3/2 Rubric Guidance — Unit Rate

4 (Expert): Both unit rates correct (7.00 ppg each); division work shown for both; interpretation stated ("they are tied — this means..."); notes the tie creates a need for further analysis.
3 (Proficient): Both unit rates numerically correct.
2 (Developing): One rate correct or division set up incorrectly (e.g., games ÷ points instead of points ÷ games).

2
Equivalent Ratios · 6.RP.1 · 6.RP.3

Compare Players Using Equivalent Ratios

Jordan pts
84
Jordan games
12
Riley pts
70
Riley games
10
Scale to (common games)
60
In 60 games: Jordan = 420 pts  |  Riley = 420 pts
Jordan scaled: Factor = 60 ÷ 12 = 5.   84 × 5 = 420 pts
Equivalent ratio: 84:12 = 420:60  (multiply both parts by 5)

Riley scaled: Factor = 60 ÷ 10 = 6.   70 × 6 = 420 pts
Equivalent ratio: 70:10 = 420:60  (multiply both parts by 6)

Both would score the same — it is a tie at 420 pts in 60 games.
Sample Expert Response

"To compare Jordan and Riley on equal footing, I scaled both to 60 games. Jordan's ratio 84:12 becomes 420:60 (multiply by 5), and Riley's ratio 70:10 becomes 420:60 (multiply by 6). Since 420 = 420, both players would score identically over 60 games, confirming the tie we saw in the unit-rate analysis."

Sample 4/3/2 Rubric Guidance — Equivalent Ratios

4 (Expert): Scaling factors shown (×5, ×6), both products correct (420, 420), explains why these are equivalent ratios ("I multiplied both parts by the same number, so the ratio stays the same"), and ties the result back to the comparison.
3 (Proficient): Both players scaled correctly to 60 games (420 pts each).
2 (Developing): One scaling correct; factor computed wrong for the other (e.g., added instead of multiplied).

3
Ratio Table · 6.RP.3

Project Stats Over a Full Season

Jordan rate (ppg)
7
Riley rate (ppg)
7
30-game projection: Jordan = 210 pts  |  Riley = 210 pts
Each row = unit rate × number of games:
Games PlayedJordan (projected pts)Riley (projected pts)Calculation
10 games70.0 pts70.0 pts7 × 10 = 70
20 games140.0 pts140.0 pts7 × 20 = 140
30 games210.0 pts210.0 pts7 × 30 = 210
Both players project to the same season total — a perfect tie. All rows are equivalent ratios (rate stays constant at 7 ppg).
Sample Expert Response

"Using each player's unit rate of 7 points per game, my ratio table projects: at 10 games both have 70 points, at 20 games both have 140 points, and at 30 games (full season) both project to 210 points. Every row is an equivalent ratio of 7:1, meaning the per-game rate never changes."

Sample 4/3/2 Rubric Guidance — Ratio Table / Projection

4 (Expert): All six table cells correct (70, 140, 210 for each player); explains the pattern ("multiply unit rate by games played"); connects the tie in projections to the recommendation section.
3 (Proficient): All six cells numerically correct.
2 (Developing): Two or more cells correct; pattern partially shown.

4
Rate Reasoning & Quick Check · 6.RP.2

Draft Decision & Quick Check

Quick Check — Unit Rate: 20 points in 5 games
What is the unit rate (points per game)?
4 points per game
20 points ÷ 5 games = 4 points per game. The JS accepts exactly the number 4.
Sample Expert Response — Scouting Report (Full Deliverable)

"Coach, I analyzed the stats for Jordan and Riley. Jordan's unit rate is 7.00 points per game (84 ÷ 12) and Riley's is also 7.00 points per game (70 ÷ 10). When I scaled both to 60 games using equivalent ratios, both players had 420 projected points — a tie. By the end of the 30-game season, both project to 210 points. Because the math shows no statistical difference, I recommend starting Jordan based on consistency: Jordan reached 7.00 ppg over 12 games (a larger sample) compared to Riley's 10 games, making Jordan's rate more reliable."

Sample 4/3/2 Rubric Guidance — Communication

4 (Expert): Scouting report cites all three math tools (unit rate numbers, equivalent-ratio scaling with factors, season projection totals); recommendation is clearly stated with a data-backed justification (even when the data shows a tie, the student reasons through sample size or another factor).
3 (Proficient): Report gives a clear recommendation with most numbers present.
2 (Developing): Vague or missing key data points (e.g., no mention of the equivalent-ratio comparison).