Multiple choice

The population of small town is increased by $\frac {15}{2}$% per annum for two years. If the present population is 73,960, then two years before the population was

  1. 68,000

  2. 70,000

  3. 64,000

  4. 60,000
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Population P * (1 + 15/200)^2 = 73960. P * (1 + 0.075)^2 = 73960. P * (1.075)^2 = 73960. P * 1.155625 = 73960. P = 73960 / 1.155625 = 64000.

AI explanation

Convert the growth rate of 15/2% to a decimal to get 7.5%, meaning the population multiplies by 1.075 each year. If P is the population 2 years ago, the equation is P multiplied by 1.075 squared equals 73960. Solving for P gives 73960 divided by 1.155625, which equals 64000. The population two years before was 64000.

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