The ratio of the number of biscuits to the number of shortbreads in a shop is 3 : 1. A biscuit costs $1.70 and a shortbread costs $0.30. If all the biscuits and shortbreads are sold, a sum of $108 will be collected. How many biscuits are there altogether?
|
Biscuits |
Shortbreads |
Total |
Number |
3 u |
1 u |
|
Value |
$1.70 |
$0.30 |
|
Total value |
5.1 u |
0.3 u |
$108 |
Amount collected if all the biscuits are sold
= 3 u x 1.7
= 5.1 u
Amount collected if all the shortbreads are sold
= 1 u x 0.3 u
= 0.3 u
Amount collected if all the biscuits and shortbreads are sold
= 5.1 u + 0.3 u
= 5.4 u
5.4 u = 108
1 u = 108 ÷ 5.4 = 20
Total number of biscuits
= 3 u
= 3 x 20
= 60
Answer(s): 60