The number of cream cakes on display at a cafe was
23 of the number of cookies on display. After 15 cream cakes were bought and the staff added another 30 cookies, the number of cookies was twice the number of cream 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?
| |
Cream cakes |
Cookies |
| Before |
2 u |
3 u |
| Change |
- 15 |
+ 30 |
| After |
2 u - 15 |
3 u + 30 |
Comparing cream cakes
and cookies
in the end |
1 |
2 |
The number of cookies was twice the number of cream cakes in the end.
Number of cookies in the end
= 2(2 u - 15)
= 4 u - 30
4 u - 30 = 3 u + 30 4 u - 3 u = 30 + 301 u = 60
1 u = 60 ÷ 1 = 60Number of cookies in the end= 3 u + 30= 3 x 60 + 30= 210Number of customers in the last group= 210 ÷ 5= 42 Answer(s): 42 
