A certain sum amounts to ₹5916 in 3 years and to ₹6960 in 5 years at simple interest.Find the sum and the rate per cent per annum.
Answers
Answer:
.
Explanation:
Formula to find The final amount after a principal amount p is invested at rate of interest r ( in decimal ) in time
A = p ( l+RT)
i.e 5916 = p ....1 by give
6960 = p (1+5r)....2 by given
Divided Equation 2 by 1
6960/5916 = p ( 1 +5r)/p ( 1+3r)
20/17 = (1 +5r)/( 1+3r)
20 ( 1+3r) = 17 ( 1+5r)
20 + 60 r = 17 + 85 r
85 - 60 = 17 -20
25 r = 3
r = 3/25
Put Value r in (1)
5916 = p ( 1+3(25/3)
5916 = p ( 26)
p = 5916/26
p = 227.54
The value r in percent = 3/25×100
4×3 = 12%
So your answers is 12%
thanks dear friend
★We know:-
S.I. for 2 years = (Amount after 5 years) - (Amount after 3 years)
= ₹ (6960 - 5916) = ₹ 1044.
S.I. for 1 year =
S.I. for 3 years = ₹ (522 × 3) = ₹ 1566
⇒Sum = (Amount after 3 years) - (S.I. for 3 years)
= ₹ (5916 - 1566) = ₹ 4350.
★Now, P = ₹ 4350, S.I. = ₹ 1566, T = 3 years.
= 12% p.a
Hence , the required sum is ₹ 4350 and the rate of interest is 12% p.a.