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percentage problem

by romitvsingh » Wed Oct 12, 2011 7:57 am
The difference between the value of a number increased by 12.5% and the value of the original number decreased by 25% is 30. What is the original number?

A. 60
B. 80
C. 40
D. 120
E. 160
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by shankar.ashwin » Wed Oct 12, 2011 8:02 am
Let the no. be x;

1.125x - 0.75x = 30

0.375x = 30

x = 80 B
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by CappyAA » Wed Oct 12, 2011 8:02 am
B

Let x be the number:

(1 + 0.125)*x - (1 - 0.25)*x = 30
1.125x - 0.75x = 30
0.375x = 30
x = 80

If you don't want to deal with decimals, you can also see that 0.125 = 1/8 and 0.75 = 3/4. This makes the problem a little easier to deal with:

9/8*x - 3/4*x = 30
3/8*x = 30
x = 80
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by parul9 » Wed Oct 12, 2011 8:08 am
1.125x - .75 x = 30
gives x = 80.

B!
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by MBA.Aspirant » Wed Oct 12, 2011 1:46 pm
1.125 x - 0.75 x = 30

x = 80
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