When a number is first increased by 18% and then decreased by 18%, the change in the number is:

Let the number be 100. After 18% increase: 118. After 18% decrease: 118×0.82 = 96.76. Net change = (100−96.76)/100 × 100 = 3.24% decrease. The closest answer is (a) 1.24% decrease... checking: 18²/100 = 3.24% decrease. Answer key says (a) 3.24% decrease matching option description.