The ratio of the number of cookies to the number of wafers in a supermarket is 2 : 1. A cookie costs $1.40 and a wafer costs $0.90. If all the cookies and wafers are sold, a sum of $37 will be collected. How many cookies are there altogether?
| |
Cookies |
Wafers |
Total |
| Number |
2 u |
1 u |
|
| Value |
$1.40 |
$0.90 |
|
| Total value |
2.8 u |
0.9 u |
$37 |
Amount collected if all the cookies are sold
= 2 u x 1.4
= 2.8 u
Amount collected if all the wafers are sold
= 1 u x 0.9 u
= 0.9 u
Amount collected if all the cookies and wafers are sold
= 2.8 u + 0.9 u
= 3.7 u
3.7 u = 37
1 u = 37 ÷ 3.7 = 10
Total number of cookies
= 2 u
= 2 x 10
= 20
Answer(s): 20
