The number of coffee cakes on display at a cafe was
34 of the number of puffs on display. After 20 coffee cakes were bought and the staff added another 40 puffs, the number of puffs was thrice the number of coffee 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?
| |
Coffee cakes |
Puffs |
| Before |
3 u |
4 u |
| Change |
- 20 |
+ 40 |
| After |
3 u - 20 |
4 u + 40 |
Comparing coffee cakes
and puffs
in the end |
1 |
3 |
The number of puffs was thrice the number of coffee cakes in the end.
Number of puffs in the end
= 3(3 u - 20)
= 9 u - 60
9 u - 60 = 4 u + 40 9 u - 4 u = 60 + 405 u = 100
1 u = 100 ÷ 5 = 20Number of puffs in the end= 4 u + 40= 4 x 20 + 40= 120Number of customers in the last group= 120 ÷ 5= 24 Answer(s): 24 
