Correct Answer - Option 3 : 3

**Given:**

The average number of crackers A and B sold in the three days is 21 and 25 respectively. The number of crackers shop A sold on Wednesday is double than the number of crackers it sold on Tuesday. The number of crackers A sold on Wednesday is one more than the number of crackers B sold on the same day. B sold 10 more crackers on Tuesday than A.

**Formula:**

Average of n numbers a1, a2 ... an = (a1 + a2 + ... an)/n

**Calculation:**

Two shops A and B sold crackers on Diwali on 3 days – Monday, Tuesday and Wednesday.

Average number of crackers shop A sold in 3 days = 21

Total crackers sold by shop A = 21 × 3 = 63

Similarly, total crackers sold by shop B = 25 × 3 = 75

Monday Tuesday Wednesday

A x 2x

B x + 10 2x - 1

Total for shop A = 63

Total for shop B = 75

A Monday = 63 -3x

B Monday = 75 – (x + 10) – (2x – 1)

75 – x – 10 – 2x + 1 – 63 + 3x = 3