alex.gellatly wrote:A certain company that sells only cars and trucks reported that revenues from car sales in 1997 where down 11 percent from 1996 and revenues from truck sales in 1997 were up 7 percent from 1996. If total revenues from car sales and truck sales in 1997 where up 1 percent, what is the ratio of revenue from car sales in 1996 to revenue from truck sales in 1996?
1:2
4:5
1:1
3:2
5:3
This is a MIXTURE problem: an 11% decrease in car revenue and a 7% increase in truck revenue are being combined to form a MIXTURE with an overall revenue increase of 1%.
The following approach is called
alligation.
It's a very good way to handle MIXTURE PROBLEMS.
Let C = car revenue and T = truck revenue.
Step 1: Plot the 3 percentages on a number line, with the two starting percentages (-11% and +7%) on the ends and the goal percentage (+1%) in the middle.
C(-11%)--------------------(+1%)--------T(+7%)
Step 2: Calculate the distances between the percentages.
C(-11%)----------
12---------(+1%)----
6----T(+7%)
Step 3: Determine the ratio in the mixture.
The ratio of C to T in the mixture is the RECIPROCAL of the distances in red.
C:T = 6:12 = 1:2.
The correct answer is
A.
For two other problems that I solved with alligation, check here:
https://www.beatthegmat.com/ratios-fract ... tml#484583Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at
[email protected].
Student Review #1
Student Review #2
Student Review #3
