GMAT Practice Question: David used part of 100,000USD to purchase a house. Of the remaining portion, he invested...
Question
David used part of 100,000USD to purchase a house. Of the remaining portion, he invested 1/3 of it at 4 percent simple annual interest and 2/3 of it at 6 percent simple annual interest. If after a year the income from the two investments totaled 320USD, what was the purchase price of the house?
- 96,000USD
- 94,000USD
- 88,000USD
- 75,000USD
- 40,000USD
Topics: word problems, percentages, interests - simple
Solution
Step 1
We name the purchase price variable and express the remaining amount to invest.
x = purchase price of the house 100000 - x = remaining amount to invest
Step 2
We calculate the weighted simple interest rate on the remaining amount.
1/3 4% + 2/3 6% = 4/3% + 4% = 16/3%
Step 3
We translate the total interest income into an equation using the percent rate and the remaining amount.
(100000 - x) 16/3100 = 320
Step 4
We solve for the remaining amount by isolating 100000 - x.
100000 - x = 320 10016/3 = 320 300/16
Step 5
We simplify the product by cancelling common factors.
320 300/16 = 16 20 30016 = 20 300 = 6000
Step 6
We subtract the remaining amount from 100000 to find the purchase price.
100000 - x = 6000 x = 100000 - 6000 = 94000
Answer
94,000USD
