Mo2men wrote:Dear GMATGuru,
While I followed your method in my original solutions, I tried to use the alligation method. I treated both M & N like a mix of water and alcohol.
I used the 'win' part of each game of M & N
Win games of M = 1/3 = 4/12
Win games of N = 1/4= 3/12
M................Mix................N
4/12...................................3/12
So difference = 1/12
However, I stumbled in the above..............How can I continue?
Can you help please? Thanks
Let S = the entire season (in other words, the mixture of M and N).
Alligation can be performed only with percentages or fractions.
Step 1: Convert the ratios to FRACTIONS.
M:
Since win:losses = 1:2, and 1+2=3, wins/total = 1/3.
N:
Since wins:losses = 1:3, and 1+3=4, wins/total = 1/4.
Step 2: Put the fractions over a COMMON DENOMINATOR.
M = 1/3 = 4/12.
N = 1/4 = 3/12.
Step 3: Plot the fractions on a number line, with M and N on the ends and S in the middle.
M 4/12-----------S-----------3/12 M
Step 4: Calculate the distances between M, S and N.
Since M:N = 4:5, the distances on the number line are yielded by the RECIPROCAL of this ratio:
5x:4x.
Plotting the distances on the number line, we get:
M 4/12----5x----S----4x----3/12 N
Step 5: Determine the value of x.
The number line indicates that the total distance (5x+4x) is equal to the difference between 4/12 and 3/12:
5x+4x = 4/12 - 3/12
9x = 1/12
x = 1/108.
Thus:
wins/total in S = (M's fraction) - 5x = 4/12 - 5(1/108) = 36/108 - 5/108 = 31/108.
Implication:
Of every 108 games, 31 games are wins, implying that the remaining 77 games are losses.
Thus in S:
wins:losses = 31:77.
The correct answer is
E.
Private 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