The number of durian cakes on display at a cafe was
23 of the number of tarts on display. After 15 durian cakes were bought and the staff added another 42 tarts, the number of tarts was twice the number of durian cakes. The last group of customers bought 6 tarts each, finishing all the tarts on display. How many customers were there in the last group?
| |
Durian cakes |
Tarts |
| Before |
2 u |
3 u |
| Change |
- 15 |
+ 42 |
| After |
2 u - 15 |
3 u + 42 |
Comparing durian cakes
and tarts
in the end |
1 |
2 |
The number of tarts was twice the number of durian cakes in the end.
Number of tarts in the end
= 2(2 u - 15)
= 4 u - 30
4 u - 30 = 3 u + 42 4 u - 3 u = 30 + 421 u = 72
1 u = 72 ÷ 1 = 72Number of tarts in the end= 3 u + 42= 3 x 72 + 42= 258Number of customers in the last group= 258 ÷ 6= 43 Answer(s): 43 
