A grocer had the same number of pomegranates, dragonfruits and grapefruits at first. After 67 grapefruits, some pomegranates and dragonfruits were used, there were 170 fruits left. There were thrice as many pomegranates as dragonfruits left. The number of grapefruits left was 40 less than the number of pomegranates. How many dragonfruits were used?
| |
Pomegranates |
Dragonfruits |
Grapefruits |
Total |
| Before |
1 |
1 |
1 |
|
| Change |
- ? |
- ? |
- 67 |
|
| After |
3 u |
1 u |
3 u - 40 |
170 |
Total number of fruits in the end
= 3 u + 1 u + 3 u - 40
= 7 u - 40
7 u - 40 = 170
7 u = 170 + 40
7 u = 210
1 u = 210 ÷ 7 = 30
Number of grapefruits at first
= 3 u - 40 + 67
= 3 x 30 - 40 + 67
= 90 - 40 + 67
= 117
The number of dragonfruits and grapefruits at first was the same.
Number of dragonfruits used
= 117 - 1 u
= 117 - 30
= 87
Answer(s): 87
