averages

This topic has expert replies
Legendary Member
Posts: 2326
Joined: Mon Jul 28, 2008 3:54 am
Thanked: 173 times
Followed by:2 members
GMAT Score:710

averages

by gmatmachoman » Fri Mar 12, 2010 9:49 am
For a recent play performance, the ticket prices were $25 per adult and $15 per child. A
total of 500 tickets were sold for the performance. How many of the tickets sold were for
adults?
(1) Revenue from ticket sales for this performance totaled $10,500.
(2) The average (arithmetic mean) price per ticket sold was $21.

Source:GMAT SETS!
Source: — Data Sufficiency |

Junior | Next Rank: 30 Posts
Posts: 20
Joined: Wed Jan 13, 2010 1:28 pm

by hooliganpete » Fri Mar 12, 2010 10:05 am
Here's my stab at it:

From the question stem we know that there are 500 tickets sold, A of which are adult tickets and C of which are child tickets. Thus, A+C=500.

1) From this we can set up the equation: revenue earned = (# adult tickets sold x price) + (# child tickets sold x price2)

or
10,500=25A+15C --> here there are 2 variables and two distinct equations. SUFFICIENT

2) Here we are given the average, thus: 21=(25A+15C)/500
Again we now have two variables and two equations, the one we derived is the same as the equations from 1). SUFFICIENT

IMO D

User avatar
Master | Next Rank: 500 Posts
Posts: 293
Joined: Thu Jan 14, 2010 9:08 am
Location: India
Thanked: 36 times
Followed by:5 members
GMAT Score:730

by mohit11 » Fri Mar 12, 2010 10:30 am
hooliganpete wrote:Here's my stab at it:

From the question stem we know that there are 500 tickets sold, A of which are adult tickets and C of which are child tickets. Thus, A+C=500.

1) From this we can set up the equation: revenue earned = (# adult tickets sold x price) + (# child tickets sold x price2)

or
10,500=25A+15C --> here there are 2 variables and two distinct equations. SUFFICIENT

2) Here we are given the average, thus: 21=(25A+15C)/500
Again we now have two variables and two equations, the one we derived is the same as the equations from 1). SUFFICIENT

IMO D
D is the answer. My reasoning is same as above.