Q17 of 52 Page 117

If the rate of increase in population is r% per year, the population after n year is p; let us find the population that was n years before.

Given : The present population = p


Let previous year’s population be x


Then,


As the population increases by rate r%




And population before n years was


More from this chapter

All 52 →
17

Let us write the rate of compound interest per annum, so that the amount on ₹400 for 2 years becomes ₹441.

 17

If a sum of money doubles itself at compound interest in n years, let us write in how many years will it become four times.

 17

Let us calculate the principal that at the rate of 5% compound interest per annum becomes ₹615 after two years.

 17

The price of a machine depreciates at the rate of r% per annum, let us find the price of the machine that was n years before.