GMAT Problem Solving (PS) | Quentin's income is 60% less than Rex's income, and Sam's income is 25

My approach :

We can take some easy numbers and make calculations simpler.
Let R ( Rex's income) = 100
Q (Quentin's income) = 40%R = 40
S (Sam's income) = 75% Q = (3/4)*40 = 30

Now, if Rex gives 40% to Quentin --> Q = 40 + 40 = 80
60% given to Sam --> S = 30+60 = 90

The ratio is : Q/S = 80/90 = 8/9

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