The number of durian cakes on display at a cafe was
56 of the number of cookies on display. After 18 durian cakes were bought and the staff added another 36 cookies, the number of cookies was twice the number of durian cakes. The last group of customers bought 6 cookies each, finishing all the cookies on display. How many customers were there in the last group?
| |
Durian cakes |
Cookies |
| Before |
5 u |
6 u |
| Change |
- 18 |
+ 36 |
| After |
5 u - 18 |
6 u + 36 |
Comparing durian cakes
and cookies
in the end |
1 |
2 |
The number of cookies was twice the number of durian cakes in the end.
Number of cookies in the end
= 2(5 u - 18)
= 10 u - 36
10 u - 36 = 6 u + 36 10 u - 6 u = 36 + 364 u = 72
1 u = 72 ÷ 4 = 18Number of cookies in the end= 6 u + 36= 6 x 18 + 36= 144Number of customers in the last group= 144 ÷ 6= 24 Answer(s): 24 
