Question

Which two signs should be interchanged to make the given equation correct?

(72 ÷ 18) + 30 × 8 − 4 = 20

• A. + and -
• B. + and ×
• C. × and ÷
• D. + and ÷

Answer 1

Answer:

D. + and ÷

Solution: 1) + and – Given equation: (72 ÷ 18) + 30 × 8 − 4 = 20 After interchanging the signs, we get: L.H.S. = (72 ÷ 18) - 30 × 8 + 4 = 4 – 240 + 4 = 8 – 240 = -232 ≠ R.H.S 2) + and × Given equation: (72 ÷ 18) + 30 × 8 − 4 = 20 After interchanging the signs, we get: L.H.S. = (72 ÷ 18) × 30 + 8 − 4 = 4 × 30 + 8 – 4 = 120 + 8 – 4 = 128 – 4 = 124 ≠ R.H.S 3) × and ÷ Given equation: (72 ÷ 18) + 30 × 8 − 4 = 20 After interchanging the signs, we get: L.H.S. = (72 × 18) + 30 ÷ 8 − 4 = 1296 + 3.75 – 4 = 1299.75 – 4 = 1295.75 ≠ R.H.S 4) + and ÷ Given equation: (72 ÷ 18) + 30 × 8 − 4 = 20 After interchanging the signs, we get: L.H.S. = (72 + 18) ÷ 30 × 8 − 4 = 90 ÷ 30 × 8 – 4 = 3 × 8 – 4 = 24 – 4 = 20 = R.H.S. Hence, ‘+ and ÷’ is the correct answer.