Lisa spends 3/8th of her salary on rent and 5/12 on food. Her roommate, Carrie earns about twice as much as Lisa, spends 1/4th of her salary on the rent and 1/2 on food. If the two women decide to contribute the rest of their salary to charity every month, what fraction of their combined monthly income will they donate.

Hi all!!! Have a small query on a ratio problem. Though it's a relatively simple question, couldn't arrive at the desired solution. it would be great if any of you could help me with this. Thanks in advance

The answer given is

but what I derived is 17/24.

Here are the steps I've followed, please correct me on this note.

x = lisa's salary from which, 3/8x=rent ; 5/12x=food ; remaining towards charity= x- 3/8x-5/12x= 5x/24;

y=Carrie's salary; 1/4y=rent;1/2y=food; charity= y-1/4y-1/2y= 1/4y

but, y=2x ( Carrie's salary twice as much as Lisa's)

Hence Carries contribution to charity= 1/4y = 1/4 *2x= 1/2x

Their combined contribution to charity = 1/2x+ 5/24x = 17/24x

Hence the desired answer is 17/24.

But , the correct answer is

Kindly, help!!!

Sandhya Iyer