The relationship between the weight W in pounds and the heig

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[GMAT math practice question]

The relationship between the weight W in pounds and the height H in inches of an object is given by the equation, W = 110 +5*(H-60). If the height is increased by 10 inches, by how much does the weight increase?

A. 30 pounds
B. 40 pounds
C. 50 pounds
D. 60 pounds
E. 70 pounds

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by swerve » Thu Jul 05, 2018 9:49 am
The only difference when H becomes H + 10 is:

5*(H - 60) - 5*(H + 10 - 60) = 300 - 250 = 50 (since 110 is constant).

Hence C is the correct answer.

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by Scott@TargetTestPrep » Sat Jul 07, 2018 5:32 pm
Max@Math Revolution wrote:[GMAT math practice question]

The relationship between the weight W in pounds and the height H in inches of an object is given by the equation, W = 110 +5*(H-60). If the height is increased by 10 inches, by how much does the weight increase?

A. 30 pounds
B. 40 pounds
C. 50 pounds
D. 60 pounds
E. 70 pounds

We can let the height H be 100, so the weight W would be 110 + 5*(100 - 60) = 110 + 200 = 310 pounds.

Since the height is increased by 10 inches, the height now is 110, so the weight now is W = 110 + 5(110 - 60) = 110 + 250 = 360 pounds.

We see that the weight is increased by 50 pounds.

Answer: C

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by Max@Math Revolution » Sun Jul 08, 2018 3:05 am
=>

From W = 110 +5*(H-60), we have W = 5H - 190, which is the equation of a line of slope 5. Since the slope is the ratio of the increase in the weight to that of the height, the weight is increased by 50 when the height is increased by 10.

Therefore, the answer is C.

Answer : C