M+J=X
(J-80)+J=X
2J-80=X
2J-80+X=2X
2J-80=X
J=(80+X)/2
Ans:40+(X/2)
dollars
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Source: Beat The GMAT — Problem Solving |
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goalevan
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We are given two equations to begin:
M + J = x, and
M = J - 80
We can calculate for Joe's current dollars in terms of x:
[J - 80] + J = x
2J - 80 = x
2J = x + 80
J = (x + 80)/2
If we add x to both sides, we will have the answer to the question in terms of x on the right side:
J + x = (x + 80)/2 + x
= (x + 80 + 2x)/2
= (3x + 80)/2
= 3x/2 + 40
C
M + J = x, and
M = J - 80
We can calculate for Joe's current dollars in terms of x:
[J - 80] + J = x
2J - 80 = x
2J = x + 80
J = (x + 80)/2
If we add x to both sides, we will have the answer to the question in terms of x on the right side:
J + x = (x + 80)/2 + x
= (x + 80 + 2x)/2
= (3x + 80)/2
= 3x/2 + 40
C
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Tani
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This question lends itself to picking numbers.
Say x = 200. Then Joe has 140 and Mary has 60.
Give Joe an additional 200, he now has 340.
Plugging 200 back into the answer choices, only C gives us 340.
Say x = 200. Then Joe has 140 and Mary has 60.
Give Joe an additional 200, he now has 340.
Plugging 200 back into the answer choices, only C gives us 340.
Tani Wolff
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MBA.Aspirant
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M+J = x
m = x- j
m + 80 = j
x - j + 80 = J
x+80 = 2J
J = 1/2 x + 40
j = 1/2x + 40 + x = 3/2 x + 40
m = x- j
m + 80 = j
x - j + 80 = J
x+80 = 2J
J = 1/2 x + 40
j = 1/2x + 40 + x = 3/2 x + 40
