Questions about the world of GRE Math from other sources and general math related questions.
baily106
Course Students
 
Posts: 49
Joined: Sat May 03, 2014 1:13 am
 

Official Guide -p. 245 q15 - Charter Plane

by baily106 Sun Jun 08, 2014 7:13 pm

A group can charter a particular aircraft at a fixed total cost. If 36 people charter the aircraft rather than 40, then the cost per person is greater by $12.
a) What is the fixed total cost to charter the aircraft?
b) What is the cost per person if 40 people charter the aircraft?

How would you approach this problem?
(p.245/q15)

Anisha
tommywallach
Manhattan Prep Staff
 
Posts: 1917
Joined: Thu Mar 31, 2011 11:18 am
 

Re: Official Guide Book Question

by tommywallach Mon Jun 09, 2014 11:02 pm

A group can charter a particular aircraft at a fixed total cost. If 36 people charter the aircraft rather than 40, then the cost per person is greater by $12.
a) What is the fixed total cost to charter the aircraft?
b) What is the cost per person if 40 people charter the aircraft?

I'd start by setting up equations using the average formula:

Cost/36 = x
Cost/40 = x - 12

Then multiply out:

Cost = 36x
Cost = 40x - 480

Then set equal:

36x = 40x - 480
4x = 480
x = 120

That's the cost per person. Total cost is just that times 36.

120 * 36 = 4320

To get cost per person at 40, just divide the result of the previous operation by 40.

4320/40 = 108

Hope that helps!

-t