Question

11. After how many years does a sum of
Rs. 500 become double at sinple interest
of 20% per annum?
1) 3 years 2) 4 years
Se
3) 5 years
4) 6 years
Ans: 5 years
16​

Answer 1

Solution

Given :-

• P = Rs 500
• r = 20%

Find :-

• t = ?

Explanation

Here ,

We want sum be double that's mean , simple interest will be same of principal .

Then, let

• C.I. = Rs 500

Now using C.I. Formula.

$\boxed{\underline{\tt{\red{\:C.I.=\:\dfrac{p\times r\times t}{100}}}}}$

Keep all values

==> 500 = 500 × 20 × t/100

==> 500 × 100/( 20 × 500) = t

==> t = 100/20

==> t = 5

Hence

• Sum of Rs 500 became double after 5 years .

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