The number of cream cakes on display at a cafe was
23 of the number of cookies on display. After 23 cream cakes were bought and the staff added another 39 cookies, the number of cookies was five times the number of cream 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?
|
Cream cakes |
Cookies |
Before |
2 u |
3 u |
Change |
- 23 |
+ 39 |
After |
2 u - 23 |
3 u + 39 |
Comparing cream cakes and cookies in the end |
1 |
5 |
The number of cookies was five times the number of cream cakes in the end.
Number of cookies in the end
= 5(2 u - 23)
= 10 u - 115
10 u - 115 = 3 u + 39 10 u - 3 u = 115 + 397 u = 154
1 u = 154 ÷ 7 = 22Number of cookies in the end= 3 u + 39= 3 x 22 + 39= 105Number of customers in the last group= 105 ÷ 7= 15 Answer(s): 15