Min wanted to buy some puffs and cookies. The cost of a puff was
17 the cost of a cookie. A set of 7 puffs and 2 cookies cost $6.30. What was the total amount Min had to pay for 9 puffs and 10 cookies?
|
Puffs |
Cookies |
Total |
Number |
7 |
2 |
|
Value |
1 u |
7 u |
|
Total value |
7 u |
14 u |
21 u |
Total cost of puffs and cookies
= 7 u + 14 u
= 21 u
21 u = 6.3
1 u = 6.30 ÷ 21 = 0.3
Cost of 9 puffs and 10 cookies
= 9 x 1 u + 10 x 7 u
= 9 u + 70 u
= 79 u
= 79 x 0.3
= $23.70
Answer(s): $23.70