The number of durian cakes on display at a cafe was
56 of the number of puffs on display. After 20 durian cakes were bought and the staff added another 40 puffs, the number of puffs was twice the number of durian cakes. The last group of customers bought 5 puffs each, finishing all the puffs on display. How many customers were there in the last group?
| |
Durian cakes |
Puffs |
| Before |
5 u |
6 u |
| Change |
- 20 |
+ 40 |
| After |
5 u - 20 |
6 u + 40 |
Comparing durian cakes
and puffs
in the end |
1 |
2 |
The number of puffs was twice the number of durian cakes in the end.
Number of puffs in the end
= 2(5 u - 20)
= 10 u - 40
10 u - 40 = 6 u + 40 10 u - 6 u = 40 + 404 u = 80
1 u = 80 ÷ 4 = 20Number of puffs in the end= 6 u + 40= 6 x 20 + 40= 160Number of customers in the last group= 160 ÷ 5= 32 Answer(s): 32 
