| Question | If the numbers 15 and 21 are interchanged, then which of the following equations will be correctly balanced? | |
| Type | multiple_choice | |
| Option | 63 ÷ 15 + 21 × 5 – 4 = 74 | correct |
| Option | 62 ÷ 31 – 21 + 15 × 3 = 80 | incorrect |
| Option | 24 – 21 ÷ 3 + 15 – 7 = 23 | incorrect |
| Option | 26 + 21 × 15 ÷ 3 – 14 = 108 | incorrect |
| Solution | 63 ÷ 15 + 21 × 5 – 4 = 74 After interchanging the number 15 and 21 in given equation the equation is as follows : 63 ÷ 21 + 15 × 5 – 4 = 74 ⇒ 63 ÷ 21 + 15 × 5 – 4 = 74 ⇒ 3 + 15 × 5 – 4 = 74 ⇒ 3 + 75 – 4 = 74 ⇒ 78 – 4 = 74 ⇒ 74 = 74 LHS = RHS | |
