A headmaster contributes 7% of his income into a fund and his wife contributes 4% of her income. If the husband earns N5,500 per annum (p.a) and the wife ea...

To find the sum of their annual contribution to the fund, we need to calculate the amount that each of them contributes and then add them up. The headmaster contributes 7% of his income, which is 7/100 * N5,500 = N385 per annum. The wife contributes 4% of her income, which is 4/100 * N4,000 = N160 per annum. Therefore, the sum of their annual contribution to the fund is N385 + N160 = N545. So, the correct answer is N545.