Princeton CAT1 PS - ratios

This topic has expert replies
Senior | Next Rank: 100 Posts
Posts: 30
Joined: Tue Mar 17, 2009 3:59 pm

Princeton CAT1 PS - ratios

by gbb » Tue Mar 17, 2009 5:51 pm
Princeton CAT1

Josh and Marcia bought a number of chairs at an auction. The average price of the chairs Marcia purchased was $50, and the average price of the chairs Josh purchased was $62. If the average price of all the chairs purchased was $53, what was the ratio of the number of chairs purchased by Marcia to the number purchased by josh?
A-1:1
B-1:2
C-1:3
D-3:1
E-2:1

answer D. I got it right using backsolving. Can someone help me to solve with algebra????

my approach:
since the average was $53, we can eliminate A,B and C, because Marcia should have purchased more chairs than Josh.
backsolving...
3:1 ratio = 4 chairs
so, 3*50 + 62 = 212 for 4 chairs, which averages 212/4=53
Source: — Problem Solving |

Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Tue Mar 17, 2009 6:02 pm
M-> No of chairs MARCIA bought
J-> No of chairs JOSE bought

50 M + 62 J = 53(M+J)

50M + 62J = 53M+53J

9J = 3M

M/J = 3/1