Question

which two signs and two numbers should be interchanged to make the given equation correct?

18 × 3 – 4 ÷ 6 + 30 = 25 × 5 ÷ 2 – 5 + 15
1. 18 and 4; 2 and 15
2. × and +; ÷ and – 
3. 4 and 30; 25 and 15
4. × and ÷ ; - and +

Answer 1

Correct Answer - Option 4 : × and ÷ ; - and +

1) By interchanging 18 to 4 and 2 to 15

4 × 3 – 18 ÷ 6 + 30 = 25 × 5 ÷ 15 – 5 + 2

4 × 3 – 3 + 30 = 25 × 0.33 – 5 + 2

12 - 3 + 30 = 8.33 - 5 + 2

39 ≠ 5.33

2) By interchanging × to + and ÷ to –

18 + 3 ÷ 4 – 6 × 30 = 25 + 5 – 2 ÷ 5 × 15

18 + 0.75 – 6 × 30 = 25 + 5 – 0.4 × 15

18 + 0.75 – 180 = 25 + 5 – 6

18.75 - 180 = 30 - 6

161.25 ≠ 24

3) By interchanging 4 to 30 and 25 to 15

18 × 3 – 30 ÷ 6 + 4 = 15 × 5 ÷ 2 – 5 + 25

18 × 3 – 5 + 4 = 15 × 2.5 – 5 + 25

54 – 5 + 4 = 37.5 – 5 + 25

58 – 5 = 62.5 – 5

53 ≠ 57.5

4) By interchanging × to ÷ and – to +

18 ÷ 3 + 4 × 6 – 30 = 25 ÷ 5 × 2 + 5 – 15

6 + 24 – 30 = 10 + 5 – 15

0 = 0

LHS = RHS

Hence “× and ÷ ; - and +” will be the answer.