Question

In the following equation, which of the two signs will be interchanged to get the correct equation?
119 - 21 ÷ 7 + 117 × 3 = 11
1. - and +
2. - and × 
3. ÷ and × 
4. ÷ and +

Answer 1

Correct Answer - Option 3 : ÷ and × 

The given equation:
119 - 21 ÷ 7 + 117 × 3 = 11
On interchanging - and +, we get:
119 + 21 ÷ 7 - 117 × 3 = 11
⇒ 119 + 3 - 351 = 11
⇒ -229 = 11 (false)
On interchanging - and ×, we get:
119 × 21 ÷ 7 + 117 - 3 = 11
⇒ 357 + 114 = 11 (false)
On interchanging ÷ and +, we get:
119 - 21 + 7 ÷ 117 × 3 = 11
⇒ 98 + 0.17 = 11 (false)
On interchanging ÷ and ×, we get:
119 - 21 × 7 + 117 ÷ 3 = 11
⇒ 119 - 147 + 39 = 11
⇒ 11 = 11 (true)

Hence, we need to interchange ÷ and × to make the equation correct.