One side of the rectangle was enlarged by 50%, and the other was reduced by 30%.

One side of the rectangle was enlarged by 50%, and the other was reduced by 30%. Reduced or increased its area and by what percentage?

The area of a rectangle is equal to the product of its sides, that is, S = a * b. One of the sides was increased by 50%, that is, a + 0.5a = a + a / 2 = (3/2) a, and the other was reduced by 30%, that is, b-0.3b = 7 / 10b, after that the area became equal to:
S = 3 / 2a * 7 / 10b = 21 / 20ab = 1 integer 1/20 ab
1/20 = 0.05, we translate into percentages, we get 5%, that is, the area has increased by 5%.