The number of banana cakes on display at a cafe was
45 of the number of cookies on display. After 15 banana cakes were bought and the staff added another 39 cookies, the number of cookies was twice the number of banana cakes. The last group of customers bought 7 cookies each, finishing all the cookies on display. How many customers were there in the last group?
| |
Banana cakes |
Cookies |
| Before |
4 u |
5 u |
| Change |
- 15 |
+ 39 |
| After |
4 u - 15 |
5 u + 39 |
Comparing banana cakes
and cookies
in the end |
1 |
2 |
The number of cookies was twice the number of banana cakes in the end.
Number of cookies in the end
= 2(4 u - 15)
= 8 u - 30
8 u - 30 = 5 u + 39 8 u - 5 u = 30 + 393 u = 69
1 u = 69 ÷ 3 = 23Number of cookies in the end= 5 u + 39= 5 x 23 + 39= 154Number of customers in the last group= 154 ÷ 7= 22 Answer(s): 22 
