GMAT Math Questions - Ratio Proportion
March 18, 2004
A, B and C, each of them working alone can complete a job in 6, 8 and 12 days respectively. If all three of them work together to complete a job and earn $ 2340, what ill be C’s share of the earnings?
| (A) | $1000 |
| (B) | $520 |
| (C) | $1080 |
| (D) | $1170 |
| (E) | $630 |
Correct choice (B) Correct Answer ($520)
Solution:
A, B and C will share the amount of $ 2340 in the ratio of the amounts of work done by them.
As A takes 6 days to complete the job, if A works alone, A will be able to complete  th of the work in a day.
Similarly, B will complete  and C will complete  of the work.
So, the ratio of the work done by A : B : C when they work together will be equal to 
Multiplying the numerator of all 3 fractions by 24, the LCM of 6, 8 and 12 will not change the relative values of the three values.
We get  = 4 : 3 : 2.
i.e., the ratio in which A: B : C will share $2340 will be 4 : 3 : 2.
Hence, C’s share will be  = 520.
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