PS

[ketkoag]

This year Henry will save a certain amount of his income, and he will spend the rest. Next year
Henry will have no income, but for each dollar that he saves this year, he will have 1 + r dollars
available to spend. In terms of r, what fraction of his income should Henry save this year so that
next year the amount he was available to spend will be equal to half the amount that he spends this
year?
A. (r+2)^-1
B.(2r+2)^-1
C.(3r+2)^-1
D.(r+3)^-1
E.(2r+3)^-1

OA: E
My answer is B.. please explain..

[Brent@GMATPrepNow]

This year Henry will save a certain amount of his income, and he will spend the rest. Next year
Henry will have no income, but for each dollar that he saves this year, he will have 1 + r dollars
available to spend. In terms of r, what fraction of his income should Henry save this year so that
next year the amount he was available to spend will be equal to half the amount that he spends this
year?
A. (r+2)^-1
B.(2r+2)^-1
C.(3r+2)^-1
D.(r+3)^-1
E.(2r+3)^-1

OA: E
My answer is B.. please explain..

Here's an algebraic solution:

[Brent@GMATPrepNow]

This year Henry will save a certain amount of his income, and he will spend the rest. Next year
Henry will have no income, but for each dollar that he saves this year, he will have 1 + r dollars
available to spend. In terms of r, what fraction of his income should Henry save this year so that
next year the amount he was available to spend will be equal to half the amount that he spends this
year?
A. (r+2)^-1
B.(2r+2)^-1
C.(3r+2)^-1
D.(r+3)^-1
E.(2r+3)^-1

OA: E
My answer is B.. please explain..

Here's a "non-algebraic" solution:

[ketkoag]

Brent, thanks a lot for your help..