please explain gmat prep question

[yvonne12]

Alice's take home pay last year was the same each month and she saved the same fraction of her take home pay each month. The total amount of the money that she had saved at the end of the year was 3 times the amount of that proportion of her monthly take home pay that she did not save. if all the money that she saved last year was her take home pay, what fraction of her take home pay did she save each month?

[800GMAT]

Let x= monthly pay
and 1/y = Fraction that she saves each month

Monthly savings = x/y
proportion of her monthly take home pay that she does not save = x - x/y


12 * x/y = 3(x - x/y)
12x/y = 3x - 3x/y
15x/y = 3x
y=5

Hence 1/5

[yvonne12]

thank you,

12 * x/y (this is 12 months times money saved) right?

[800GMAT]

Yes..right... the annual savings

[Cybermusings]

Folks this question has been discussed in a real old thread!