A puppy’s weight increased from 12 pounds to 15 pounds. By what percentage did the puppy’s weight increase?

Work Shown:

A = old value = 12 pounds

B = new value = 15 pounds

C = percent change

C = [ (B-A)/A ] * 100%

C = [ (15-12)/12 ] * 100%

C = (3/12)*100%

C = 0.25*100%

C = 25%

The positive C value indicates a percent increase

So effectively, we find the difference or change in weight (B-A) and divide it over the original weight (A). That leads to 0.25 which converts to 25%

Note that,

25% of 12 = 0.25*12 = 3

This says that the puppy gained 3 pounds, which is the value of B-A

Since the puppy gained 3 pounds, the new weight is 12+3 = 15 pounds

As an alternative, we could divide the two values B over A to find that

B/A = 15/12 = 1.25

Then subtract 1 from this result: 1.25 - 1 = 0.25 = 25%