Step-by-step explanation:
divide 3.5 by 5.0 (3.5 ÷ 5.0 = 0.7), then multiply 0.7 by 15.0 (0.7 × 15.0 = 10.5), and check by dividing (10.5 ÷ 15.0 = 7.0) the answer is 10.5
