Question

(1) If a principal becomes twice of it in 10 years, then the rate of simple
interest per annum is- (a) 5% (b) 10% (c) 15% (d) 20%.
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Answer 1

Answer:

10 percent

Step-by-step explanation:

We know,

A = P + I , where P is Principal

I is Interest and

A is amount

It is given that A = 2P

=> 2P = P + I

=> P = I , i.e Pricipal is equal to Interest

BUT WE ALSO KNOW THAT ,

I = PRT

100

Therefore,

PRT = P

100

=> RT = 100

So, R = 100

T

Here T = 10 yrs

So R = 100/10 = 10 PERCENT

Answer 2

Given - Principal becomes twice of amount in 10 years

Find - Rate of simple interest

Solution - To find simple interest, we use the formula SI = P*R*T/100. This formula has P for principal amount, r for rate of interest and t for time period.

As question mentions, A = 2P and we know Amount = Principal + Interest.

So, 2P = P + I

Therefore, Interest = Principal

Now, solving to find rate of interest.

P = P*R*10/100

100P/P = 10R

R = 10%

Hence, rate of interest is 10% per annum.