Which two numbers should be interchanged to make the given equation correct?
24 - 34 × 6 ÷ 2 + 55 = 15

Given:

24 - 34 × 6 ÷ 2 + 55 = 15

As per the options - 

(a) After interchanging 6 and 15 we get following equation - 

24 - 34 × 15 ÷ 2 + 55 = 6

24 - 34 × 7.5 + 55 = 6

24 - 255 + 55 = 6

79 - 255 = 6

(b) After interchanging  24 and 2 we get following equation - 

2 - 34 × 6 ÷ 24 + 55 = 15

2 - 34 × $$\frac{1}{4}$$​ + 55 = 15

2 - 8.5 + 55 = 15

57 - 8.5 = 15

​48.5 $$\not=$$​ 15

(c) After interchanging 15 and 34 we get following equation - 

24 - 15 × 6 ÷ 2 + 55 = 34

24 - 15 × 3 + 55 = 34

24 - 45 + 55 = 34

79 - 45 = 34

Correct answer is (c).