The ratio of the number of biscuits to the number of cookies in a stall is 4 : 1. A biscuit costs $1.80 and a cookie costs $0.70. If all the biscuits and cookies are sold, a sum of $158 will be collected. How many biscuits are there altogether?
| |
Biscuits |
Cookies |
Total |
| Number |
4 u |
1 u |
|
| Value |
$1.80 |
$0.70 |
|
| Total value |
7.2 u |
0.7 u |
$158 |
Amount collected if all the biscuits are sold
= 4 u x 1.8
= 7.2 u
Amount collected if all the cookies are sold
= 1 u x 0.7 u
= 0.7 u
Amount collected if all the biscuits and cookies are sold
= 7.2 u + 0.7 u
= 7.9 u
7.9 u = 158
1 u = 158 ÷ 7.9 = 20
Total number of biscuits
= 4 u
= 4 x 20
= 80
Answer(s): 80
