Problem Solving

BTGmoderatorLU wrote:Source: GMAT Paper Tests

Kim has 40 percent more money than Sal and Sal has 20 percent less money than Phil. If Sal and Phil have a combined total of $1.80, how much money does Kim have?

A. $1.00
B. $1.12
C. $1.20
D. $1.32
E. $1.40

The OA is B

Let x = Phil's money

Sal has 20 percent LESS money than Phil
So, Sal's money = (Phil's money) - (20% Phil's money)
= x - (20% of x)
= x - 0.2x
= 0.8x

Kim has 40 percent more money than Sal
So, Kim's money = (Sal's money) + (40% Sal's money)
= (0.8x) + (40% of 0.8x)
= (0.8x) + (0.4)(0.8x)
= 0.8x + 0.32x
= 1.12x



If Sal and Phil have a combined total of $1.80, how much money does Kim have?
We can write: 0.8x + x = 1.80
Simplify: 1.8x = 1.80
Solve: x = 1.80/1.8 = 1

We know that Kim's money = 1.12x
Since x = 1, we get: 1.12(1) = 1.12

Answer: B

Cheers,
Brent

Hi All,

We're told that Kim has 40 percent MORE money than Sal, Sal has 20 percent LESS money than Phil and Sal and Phil have a combined total of $1.80. We're asked for the amount of money that Kim has. This question can be approached in a couple of different ways, including some brute-force Arithmetic and logic.

To start, we know the most about Phil and Sal, so we should think about a pair of values that would include a number that is 20% LESS than another number. Since we're dealing with dollars and cents, let's think about round-numbers just for a moment... What would we end up with if Phil had exactly $1.00?

20% of $1.00 = $0.20, so Sal would have $1.00 - $0.20 = $0.80
In this example, Phil + Sal would total $1.00 + $0.80 = $1.80... that's EXACTLY what the prompt tells us, so we now know exactly what Phil and Sal each have.

At this point, there's just one more step... Kim has 40% MORE money than Sal...
$0.80 + (4)($0.80) = $0.80 + $0.32 = $1.12

Final Answer: B

GMAT assassins aren't born, they're made,
Rich