The number of mocca cakes on display at a cafe was
45 of the number of biscuits on display. After 20 mocca cakes were bought and the staff added another 31 biscuits, the number of biscuits was thrice the number of mocca 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?
| |
Mocca cakes |
Biscuits |
| Before |
4 u |
5 u |
| Change |
- 20 |
+ 31 |
| After |
4 u - 20 |
5 u + 31 |
Comparing mocca cakes
and biscuits
in the end |
1 |
3 |
The number of biscuits was thrice the number of mocca cakes in the end.
Number of biscuits in the end
= 3(4 u - 20)
= 12 u - 60
12 u - 60 = 5 u + 31 12 u - 5 u = 60 + 317 u = 91
1 u = 91 ÷ 7 = 13Number of biscuits in the end= 5 u + 31= 5 x 13 + 31= 96Number of customers in the last group= 96 ÷ 4= 24 Answer(s): 24 
