The ratio of lemons to grapefruits is 3 : 7. If 60 grapefruits are added, the ratio of lemons to grapefruits will be 1 : 4. How many lemons are there?
| |
Lemons |
Grapefruits |
| Before |
3x1 =
3 u |
7x1 =
7 u |
| Change |
|
+ 60 |
| After |
1x3 =
3 u |
4x3 =
12 u |
The number of lemons at first and in the end remains unchanged. Make the number of lemons at first and in the end the same. LCM of 3 and 1 is 3.
Number of grapefruits added
= 12 u - 7 u
= 5 u
5 u = 60
1 u = 60 ÷ 5 = 12
Number of lemons
= 3 u
= 3 x 12
= 36
Answer(s): 36
