The difference between the value obtained by increasing a number by 12.5% and the value obtained by decreasing the number by 6.25% is 120. What is the original number.
OA: 640
OA: 640
Here's one approach:vinay1983 wrote:The difference between the value obtained by increasing a number by 12.5% and the value obtained by decreasing the number by 6.25% is 120. What is the original number.
OA: 640
12.5% = 1/8
Since 6.25% is half as big as 12.5%, we can conclude that 6.25% = 1/16
Let x be the original number.
Increasing x by 12.5% is the same as increasing x by 1/8, so we get (9/8)x
Decreasing x by 6.25% is the same as decreasing x by 1/16, so we get (15/16)x
If the difference is 120, we can write: (9/8)x - (15/16)x = 120
Eliminate the fractions by multiplying both sides by 16: 18x - 15x = 1920
Simplify: 3x = 1920
Solve: x = 640
Cheers,
Brent
