A store owner had the same number of grapefruits, dragonfruits and kiwis at first. After 67 kiwis, some grapefruits and dragonfruits were thrown away, there were 150 fruits left. There were twice as many grapefruits as dragonfruits left. The number of kiwis left was 10 fewer than the number of grapefruits. How many dragonfruits were thrown away?
| |
Grapefruits |
Dragonfruits |
Kiwis |
Total |
| Before |
1 |
1 |
1 |
|
| Change |
- ? |
- ? |
- 67 |
|
| After |
2 u |
1 u |
2 u - 10 |
150 |
Total number of fruits in the end
= 2 u + 1 u + 2 u - 10
= 5 u - 10
5 u - 10 = 150
5 u = 150 + 10
5 u = 160
1 u = 160 ÷ 5 = 32
Number of kiwis at first
= 2 u - 10 + 67
= 2 x 32 - 10 + 67
= 64 - 10 + 67
= 121
The number of dragonfruits and kiwis at first was the same.
Number of dragonfruits thrown away
= 121 - 1 u
= 121 - 32
= 89
Answer(s): 89
