Question : Directions: Which two numbers (not digits) need to be interchanged to make the given equation correct?
83 + 711 – 95 ÷ 9 × 2 = 20

Option 1: 9 and 2

Option 2: 711 and 95

Option 3: 95 and 83

Option 4: 2 and 83

Correct Answer: 711 and 95

Solution : Given:
83 + 711 – 95 ÷ 9 × 2 = 20

Let's check each option –
First Option: 9 and 2
On interchanging the numbers, we get –
83 + 711 – 95 ÷ 2 × 9 = 20
On solving the L.H.S. of the equation –
= 83 + 711 – 95 ÷ 2 × 9
= 83 + 711 – 47.5 × 9
= 83 + 711 – 427.5
= 366.5 ≠ 20
Second Option: 711 and 95
On interchanging the numbers, we get –
83 + 95 – 711 ÷ 9 × 2 = 20
On solving the L.H.S. of the equation –
= 83 + 95 – 711 ÷ 9 × 2
= 83 + 95 – 79 × 2
= 83 + 95 – 158
= 20
Third Option: 95 and 83
​​​​​​​On interchanging the numbers, we get –
95 + 711 – 83 ÷ 9 × 2 = 20
On solving the L.H.S. of the equation –
= 95 + 711 – 83 ÷ 9 × 2
= 95 + 711 – 18.44
= 787.56 ≠ 20
Fourth Option: 2 and 83
​​​​​​​On interchanging the numbers, we get –
2 + 711 – 95 ÷ 9 × 83 = 20
On solving the L.H.S. of the equation –
= 2 + 711 – 95 ÷ 9 × 83
= 2 + 711 – 876.11
= –163.11 ≠ 20

So, the second option satisfies the equation. Hence, the second option is correct.