Question

Sonia borrowed Rs 15, 000 from Friend’s Co – operative Bank and returned an amount of Rs 15, 315 with interest after 219 days. Find the simple interest paid and the rate of interest

Answer 1

So let's begin
to find the simple interest we have to simply substract the principal from the amount

so
Amount = 15,315
Principal = 15,000
Therefore Simple Interest = 15,315 - 15,000
= 315
So Simple Interest paid = Rs. 315
Now for rate of interest , we will use the things that are given in the question
we know,
S.I. = (p × r × t) / 100

Now S.I. = Rs. 315
p = 15,000
r = r (Let) {Note - rate is simple interest per year so the time should also be in year }
Therefore t = 219 days
to convert it into year
we know , 1 year = 365 days
or , 365 days = 1 year
or, 1 day = 1/365 year
or, 219 days = 1/365 × 219 year
or 219 days = 3/5 year ( divided by 73)
Now,

S.I. = (p × r × t) / 100
or , 315 = (15,000 × r × 3/5)/100
or, 315 = (30 × r × 3){ divided 15,000 by 100 to get 150 and divided 150 by 5 to get 30}
or, 315/90 = r
or , 3.5 = r
So , the rate is 3.5 % per annum
and the simple interest is 315 .
Ans