Bunuel wrote:
In 2004, 2,400 condos sold, 15% of the total housing units sold that year. How many units sold in 2004 were not condos?
(A) 16,000
(B) 13,600
(C) 12,400
(D) 11, 200
(E) 8,600
We can solve the question with
equivalent ratiosIf 15% of the units sold WERE condos, then 85% of the units sold new NOT condos.
So we want to determine the number of sold units that represent 85% of all units sold
We'll use the ratio: (
number of units sold)/(
percent of units sold)
Let x = the number of NON-CONDO units sold that represent 85% of all units sold
We get: (
2400)/(
15) = (
x)/(
85)
Cross multiply to get: (15)(x) = (2400)(85)
Divide both sides by 15 to get: x = (2400)(85)/(15)
Evaluate: 13,600
Answer: B
------------------------
We can also solve this with a little
number senseIf 15% of the units sold WERE condos, then
85% of the units sold new NOT condos.
GIVEN: 2,400 represents 15% of the total housing units sold that year
So, 4,800 must represent 30% of the total housing units sold that year
And 9,600 must represent 60% of the total housing units sold that year
And
14,400 must represent
90% of the total housing units sold that year
Oops, we went too far. We need to subtract 5% worth of housing units to get down to the desired
85%
If 2,400 represents 15% of the total housing units sold that year. . .
Then
800 must represent 5% of the total housing units sold that year
So,
85% of the housing units sold =
14,400 -
800 =
13,600Answer: B
Cheers,
Brent