# IndigoLearn

##### IndigoLearn

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Sir can u please suggest me how to solve 13 problem

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sai t

CA Foundation

295

25-Feb-21 21:50

30

There are 2 methods Given: b( birth rate)=39.4/1000, d(death rate)= 19.4/1000 b-d= 39.4-19.4=20/1000 (i.e.0.02=2%) P( population) = 2P( population) To find: n=? Solution :Let's assume P=1000 applying formula: An= p(1+i)^n Putting values: 2000=1000(1+0.02)^n 2=1.02^n n=35 years. Alternative(short method) : the Rule of 70 which is a simple way to calculate the approximateÂ number of years it takes for the level of a variable growing at a constant rate to double. This rule states that the approximate number of years n for a variable growing at the constant growth rate of RÂ percent, to double is n = 70/R Since B-D = 39.4-19.4 = 20 normalized to 1000 = 2% The n = 70/2 = 35

CA Inter

2K+

26-Feb-21 09:22

Is rule 70 is applicable to ca foundation level

You can always use rule of 69,70 or 71 to approximate the answer.

Suraj Lakhotia

26-Feb-21 16:13

You can always use rule of 69,70 or 71 to approximate the answer.

where this rule available sir is this was taught in videos sir

sai t

CA Foundation

295

26-Feb-21 17:20

Is rule 70 is applicable to ca foundation level

Basically its is "rule of 72" is simple way to determine how long will ur investment 'double' given in fixed annual rate..but i used 70 in this sum for just convenience thats it. Remember if something increase in fixed annual rate(R) and u required to find a time(N) in certain interest to take the value double. U can use "rule of 72" for to get aprox answer N=72/R

CA Inter

2K+

26-Feb-21 21:28

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