Question

Which two signs and two numbers should be interchanged in the following equation to make it correct?

40 × 4 – 10 ÷ 5 + 22 = 50

1. × and ÷, 22 and 40
2. + and –, 22 and 40
3. + and ×, 4 and 5
4. – and ÷, 10 and 40

Answer 1

Correct Answer - Option 2 : + and –, 22 and 40

By checking the options :

1) × and ÷, 22 and 40

Given equation: 40 × 4 – 10 ÷ 5 + 22 = 50

After interchanging the symbol according to the option.

⇒ 22 ÷ 4 – 10 × 5 + 40 = 50

⇒ 5.5 – 50 + 40 = 50

⇒ -4.5 ≠ 50 

2) + and –, 22 and 40

Given equation: 40 × 4 – 10 ÷ 5 + 22 = 50

After interchanging the symbol according to the option.

⇒ 22 × 4 + 10 ÷ 5 – 40 = 50

⇒​ 88 + 2 – 40 = 50

⇒ 90 – 40 = 50

⇒ 50 = 50

3) + and ×, 4 and 5

Given equation: 40 × 4 – 10 ÷ 5 + 22 = 50

After interchanging the symbol according to the option.

⇒ 40 + 5 – 10 ÷ 4 × 22 = 50

⇒ 40 + 5 – 2.5 × 22 = 50

⇒ 40 + 5 – 55 = 50

⇒ 45 – 55 = 50

⇒ -10 ≠ 50

4) – and ÷, 10 and 40

Given equation: 40 × 4 – 10 ÷ 5 + 22 = 50

After interchanging the symbol according to the option.

⇒ 10 × 4 ÷ 40 – 5 + 22 = 50

⇒ 10 × 0.1 – 5 + 22 = 50

⇒ 1 – 5 + 22 = 50

⇒ 23 – 5 = 50

⇒ 18 ≠ 50

Hence, “+ and -, 22 and 40” is the correct answer.