Q16 of 62 Page 121

The population of a town increases by 8% annually. If the present population is 54000, what was it a year ago?

Let population of the town a year ago = Z


∴ Present population = 108% of Z


⇒ 54000 = Z × 108/100


⇒ 54000 = Z × 27/25


⇒ Z = 54000 × 25/27


⇒ Z = 2000 × 25


⇒ Z = 50000


More from this chapter

All 62 →
14

A’s income is 20% less than that of B. By what per cent is B’s income more than A’s?

 15

The price of petrol goes up by 10%. By how much per cent must a motorist reduce the consumption of petrol so that the expenditure on it remains unchanged?

 17

The value of a machine depreciates every year by 20%. If the present value of the machine be Rs. 160000, what was its value last year?

 18

An alloy contains 40% copper, 32% nickel and rest zinc. Find the mass of zinc in one kg of the alloy.