The number of cream cakes on display at a cafe was
23 of the number of biscuits on display. After 24 cream cakes were bought and the staff added another 31 biscuits, the number of biscuits was twice the number of cream cakes. The last group of customers bought 4 biscuits each, finishing all the biscuits on display. How many customers were there in the last group?
| |
Cream cakes |
Biscuits |
| Before |
2 u |
3 u |
| Change |
- 24 |
+ 31 |
| After |
2 u - 24 |
3 u + 31 |
Comparing cream cakes
and biscuits
in the end |
1 |
2 |
The number of biscuits was twice the number of cream cakes in the end.
Number of biscuits in the end
= 2(2 u - 24)
= 4 u - 48
4 u - 48 = 3 u + 31 4 u - 3 u = 48 + 311 u = 79
1 u = 79 ÷ 1 = 79Number of biscuits in the end= 3 u + 31= 3 x 79 + 31= 268Number of customers in the last group= 268 ÷ 4= 67 Answer(s): 67 
