Let’s solve each problem one by one. We’ll use proportions — that means we set up two equal ratios to find the missing number.
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Problem 1:
Aiden found 6 pieces of milk chocolate in 2 boxes. How many in 12 boxes?
We can think:
If 2 boxes → 6 pieces
Then 1 box → 3 pieces (because 6 ÷ 2 = 3)
So 12 boxes → 12 × 3 =
36 pieces
Or using proportion:
6 / 2 = x / 12
Cross multiply: 2x = 72 → x = 36
✔ Answer:
36
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Problem 2:
Bookstore sold 16 books in 5 days. How many days to sell 96 books?
First, find how many books per day:
16 books ÷ 5 days = 3.2 books per day
Now, divide total books by daily rate:
96 ÷ 3.2 = ?
Let’s calculate:
3.2 × 30 = 96 → So it takes
30 days
Or using proportion:
16 / 5 = 96 / x
Cross multiply: 16x = 480 → x = 30
✔ Answer:
30 days
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Problem 3:
Steve washed 15 cars in 3 hours. How many in 7 hours?
Cars per hour: 15 ÷ 3 = 5 cars/hour
In 7 hours: 5 × 7 =
35 cars
Proportion:
15 / 3 = x / 7
Cross multiply: 3x = 105 → x = 35
✔ Answer:
35 cars
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Problem 4:
Photographer takes 12 pictures in 5 minutes. How long for 132 pictures?
Pictures per minute: 12 ÷ 5 = 2.4 pictures/minute
Time for 132: 132 ÷ 2.4 = ?
Calculate:
2.4 × 55 = 132 → So
55 minutes
Proportion:
12 / 5 = 132 / x
Cross multiply: 12x = 660 → x = 55
✔ Answer:
55 minutes
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Problem 5:
12 rotten tomatoes in every 4 boxes. How many in 14 boxes?
Rotten per box: 12 ÷ 4 = 3 per box
In 14 boxes: 3 × 14 =
42
Proportion:
12 / 4 = x / 14
Cross multiply: 4x = 168 → x = 42
✔ Answer:
42 rotten tomatoes
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Problem 6:
Pack of 6 cans costs $12. How much for 18 cans?
Cost per can: $12 ÷ 6 = $2 per can
18 cans: 18 × $2 =
$36
Proportion:
12 / 6 = x / 18
Cross multiply: 6x = 216 → x = 36
✔ Answer:
$36
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Final Answer:
1) 36
2) 30 days
3) 35 cars
4) 55 minutes
5) 42 rotten tomatoes
6) $36
Parent Tip: Review the logic above to help your child master the concept of proportion worksheet 7th grade.
