Manhattan Free CAT QUESTION-Spending limit

[dilip.aditya]

Hello Sir/Mam

I am a GMAT aspirant.Below is one of the question which appeared in Free Manhattan CAT i appeared today and i see flaw in the solution provided.The amount unspent on a credit card will be balance left.Afterall ,one can spend only that amount which is left after one has already spent some portion of the same.In below question,Sally has 1/3 balance on her Gold card which she transfers to Her platinum card which already has 1/5 balance amount(i understand,it is amount that one can utilize).On adding both,total amount becomes 11/30 of original spending limit of platinum card.Shouldn't this be the correct answer as amount remaining unspent is a balance on a credit card and not an amount which has already been spent.

Kindly Respond
Dilip Singh


Sally has a gold credit card with a certain spending limit, and a platinum card with twice the spending limit of the gold card. Currently, she has a balance on her gold card that is 1/3 of the spending limit on that card, and she has a balance on her platinum card that is 1/5 of the spending limit on that card. If Sally transfers the entire balance on her gold card to her platinum card, what portion of her limit on the platinum card will remain unspent?
11/30
29/60
17/30
19/30

11/15
Since we are not given any actual spending limits, we can pick numbers. In problems involving fractions, it is best to pick numbers that are multiples of the denominators.

We can set the spending limit for the gold account at $15, and for the platinum card at $30. In this case, Sally is carrying a balance of $5 (which is 1/3 of $15) on her gold card, and a balance of $6 (1/5 of $30) on her platinum card. If she transfers the balance from her gold card to her platinum card, the platinum card will have a balance of $11. That means that $19 out of her $30 spending limit would remain unspent.

Alternatively, we can solve this algebraically by using the variable x to represent the spending limit on her platinum card:

(1/5)x + (1/3)(1/2)x =
(1/5)x + (1/6)x =
(6/30)x + (5/30)x =
(11/30)x

This leaves 19/30 of her spending limit untouched.

The correct answer is D.

[tim]

i'm afraid i don't understand your question. you seem to agree that the platinum card is 11/30 used up, leaving 19/30 which is the correct answer. what is the concern?