hyderabad doubt

[SoniaKapoor]

An economy is growing every yr by 10% and its population is growing every yr by 2%.then in how many years will its per capita income double?

[Akshay Jain]

let GDP=X and population is Y...per capita GDP is X/Y...X is increasin @10%/annum and Y is increasin @ 2%/annum
per capita GDP after 1 year is X(1.1)/Y(1.02)
per capita GDP after n years is X/Y*(1.1/1.02)^n
find n such dat X/Y becomes 2X/Y
so we have the equation
2=(1.1/1.02)^n
n is approx equal to 9

[don123]

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[XIPP]

How did you get 0.7?

[Akshay Jain]

yup...it can be done....growth factor per year is 1.1-1.02=1.08
find n such dat (1.08)^n=2
n=9

[don123]

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[econ14]

Akshay sir u'r very intelligent