Question

The population of a village was decreasing every year due to migration ,poverty and unemployment. the present population of the village is 315840. last year migration rate 4% and the year before that it was 6% . what was the population two years ago?

Answer 1

Answer:  Population two years ago was 3,50,000

Step-by-step explanation:

Suppose there was x population two years ago.

Now,

the population migrated a year ago was 6%  i.e. 0.06

hence, the population left was

x  - (o.o6)x   .................... suppose this with a variable as y

thus, x  - (o.o6)x=y

Now, population left was y. But again this year 4% people i.e. 0.04 migrated.

Hence, present population left was  

y - (0.04)y

Y{1- 0.04}= y {0.96}

But, acc' to the question, the present population is 315840.

Thus,  y{0.96}= 315840

substituting value of y in terms of x. we get,

x{1-0.06}{0.96}= 315840

x  * 0.94*0.96= 315840

solving this we get,

X= 3,50,000.

Thus, population two years ago was x i.e. 3,50,000.

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Thanks!!..:)