Given equation: 6 × 3 + 8 ÷ 2 + 21 + 5 × 4 – 14 ÷ 7 = 53
Option 1)Â 8 and 4
Two numbers need to be interchanged then:
⇒ 6 × 3 + 4 ÷ 2 + 21 + 5 × 8 – 14 ÷ 7 = 53
⇒ 6 × 3 + 2 + 21 + 5 × 8 – 2 = 53
⇒ 18 + 2 + 21 + 40 – 2 = 53
⇒ 81 – 2 = 53
⇒ 79 ≠53
Option 2)Â 3 and 5
Two numbers need to be interchanged then:
⇒ 6 × 5 + 8 ÷ 2 + 21 + 3 × 4 – 14 ÷ 7 = 53
⇒ 6 × 5 + 4 + 21 + 3 × 4 – 2 = 53
⇒ 30 + 4 + 21 + 12 – 2 = 53
⇒ 67 – 2 = 53
⇒ 65 ≠ 53
Option 3)Â 2 and 4
Two numbers need to be interchanged then:
⇒ 6 × 3 + 8 ÷ 4 + 21 + 5 × 2 – 14 ÷ 7 = 53
⇒ 6 × 3 + 2 + 21 + 5 × 2 – 2 = 53
⇒ 2 + 2 + 21 + 10 – 2 = 53
⇒ 35 – 2 = 53
⇒ 33 ≠ 53
Option 4)Â 21 and 14
Two numbers need to be interchanged then:
⇒ 6 × 3 + 8 ÷ 2 + 14 + 5 × 4 – 21 ÷ 7 = 53
⇒ 6 × 3 + 4 + 14 + 5 × 4 – 3 = 53
⇒ 18 + 4 + 14 + 20 – 3 = 53
⇒ 56 – 3 = 53
⇒ 53 = 53
Hence, the correct answer is "21 and 14".