Question

16 In how many years will be a sum of Rs 2000 amount to Rs 2315
at 4.5 % p.A.
a) 3 year b) 4 years
c)3.5 years d) 5 years​

Answer 1

Solution!!

The concept of simple interest has to be used here. The principal, rate of interest and amount is given in the question. We have to find the time.

Principal (P) = Rs 2000

Amount = Rs 2315

Rate of interest (R) = 4.5%

Time (T) = ?

Let's find the interest first!

Amount = Principal + Interest

2315 = 2000 + Interest

Interest = 2315 - 2000

Interest = Rs 315

Now, let's find the time!

Interest = (P × R × T)/100

315 = (2000 × 4.5 × T)/100

315 = 20 × 4.5 × T

315 = 90 × T

T = 315 ÷ 90

T = 3.5

Hence, the time is 3.5 years.

The questioner may ask you to find the amount also. So, here's how you can find it.

Amount = Principal + Interest

Answer 2

Answer:

$\huge \bf \pink{3.5 \: years}$

Step-by-step explanation:

$\bf \blue{the \: first \: interest =2315-2000=315}$

$\bf \red{I = P × R ×N}$

$\bf \green{315=2000 × 4.5 × \frac{N}{100} }$

$\: \: \: \: \bf \orange{N = 315\times \frac{100}{2000} ×4.5}$

$\: \: \: \: \: \: \: \: \: \bf \purple{ = 3.5 y}$

$\bf { year = 3.5}$