The ratio of the number of wafers to the number of tarts in a stall is 3 : 1. A wafer costs $1.40 and a tart costs $0.40. If all the wafers and tarts are sold, a sum of $138 will be collected. How many wafers are there altogether?
| |
Wafers |
Tarts |
Total |
| Number |
3 u |
1 u |
|
| Value |
$1.40 |
$0.40 |
|
| Total value |
4.2 u |
0.4 u |
$138 |
Amount collected if all the wafers are sold
= 3 u x 1.4
= 4.2 u
Amount collected if all the tarts are sold
= 1 u x 0.4 u
= 0.4 u
Amount collected if all the wafers and tarts are sold
= 4.2 u + 0.4 u
= 4.6 u
4.6 u = 138
1 u = 138 ÷ 4.6 = 30
Total number of wafers
= 3 u
= 3 x 30
= 90
Answer(s): 90
