In terms of

[TuanNguyen87]

Q. 124, pg. 168, GMAT The Official Guide 11th Edition:

According to a car dealer's sales report, 1/3 of the cars sold during a certain period were sedans and 1/5 of the other cars sold were station wagons. If N station wagons were sold during the period, how many sedans, in terms of N, were sold?

I don't understand the explanation in the book and it's kinda complicated to remember. Thus, please help me to deal with this. Thanks a lot in advance!

[cans]

let total=m
no. of sedans sold = (1/3)*m
other cars = total - sedans = m - m/3 = 2m/3
station wagons = (1/5)*(2m/3) = 2m/15
2m/15=n
m=15n/2
thus sedans = m/3 = 5n/2

[TuanNguyen87]

I'm sorry that I forgot to write the answer choices:

A. 2N/15
B. 3N/5
C. 5N/3
D. 5N/2
E. 15N/2

Yeah the correct one is D. 5N/2

Thanks a lot Cans

[aftableo2006]

5N/2 is the right answer

[GMATGuruNY]

Q. 124, pg. 168, GMAT The Official Guide 11th Edition:

According to a car dealer's sales report, 1/3 of the cars sold during a certain period were sedans and 1/5 of the other cars sold were station wagons. If N station wagons were sold during the period, how many sedans, in terms of N, were sold?

I don't understand the explanation in the book and it's kinda complicated to remember. Thus, please help me to deal with this. Thanks a lot in advance!

A. 2N/15
B. 3N/5
C. 5N/3
D. 5N/2
E. 15N/2

Let cars = 15.
Sedans = (1/3)*15 = 5.
Other cars = 15-5 = 10.
N = station wagons = (1/5)*10 = 2.

Since the question asks for the number of sedans, our target is 5.
Now we plug N=2 into the answers to see which yields our target of 5.

Only answer choice D works:
(5/2)N = (5/2)*2 = 5.

The correct answer is D.