City A has a population of 136000 which is decreasing at the rate of 2400 per year , City B has a population of 84000 which is increasing at the rate of 1600 per year . In how many years will the population of two cities become equal ?
Correct Answer: 13
Explanation:
Let population of cities A and B become equal after x year.
According to the question.
Population of city A = Population of city B
Then,
136000 - 2400 x = 84000 + 1600 x.
⇒ 4000x = 52000
∴ x = 52/4 = 13 year
