Two methods:
Method 1.
We are increasing, let us find 15% of 4.25
= 15/100 * 4.25 5 into 15 and 100
= 3/20 * 4.25 2 into 20 and 4.25
= 3/10 * 2.125
= 3*2.125 / 10 = 6.375/10 = 0.6375
We add this answer to 4.25.
0.6375 + 4.25 = 4.8875
Method 2:
Increasing by 15% : (100 + 15) = 115%
We find 115% of 4.25
115 / 100 * 4.25 = 1.15 * 4.25 = 4.8875. Use your calculator.