The number of durian cakes on display at a cafe was
23 of the number of cookies on display. After 17 durian cakes were bought and the staff added another 34 cookies, the number of cookies was five times the number of durian cakes. The last group of customers bought 5 cookies each, finishing all the cookies on display. How many customers were there in the last group?
| |
Durian cakes |
Cookies |
| Before |
2 u |
3 u |
| Change |
- 17 |
+ 34 |
| After |
2 u - 17 |
3 u + 34 |
Comparing durian cakes
and cookies
in the end |
1 |
5 |
The number of cookies was five times the number of durian cakes in the end.
Number of cookies in the end
= 5(2 u - 17)
= 10 u - 85
10 u - 85 = 3 u + 34 10 u - 3 u = 85 + 347 u = 119
1 u = 119 ÷ 7 = 17Number of cookies in the end= 3 u + 34= 3 x 17 + 34= 85Number of customers in the last group= 85 ÷ 5= 17 Answer(s): 17 
