Question

The simple interest on a certain sum for 4 years at 10% p.a.is Rs 105 less than the simple interest on the same for 3 years at 15% p.a. find the sum.​

Answer 1

Answer:

1600

Step-by-step explanation:

Let P be the principal sum.

As we know that,

S.I.=

100

P×r×t

Whereas,

S.I.= Simple interest

P= Principal sum

r= Rate

t= times

Therefore,

Condition I:- For 3 years at the rate of 8% per annum.

S.I.=

100

P×8×3

.....(1)

condition II:- For 2 years at the rate of 9% per annum.

S.I.=

100

P×9×2

.....(2)

Now according to the question-

100

P×8×3

=

100

P×9×2

+96

⇒

100

P×24

=

100

(P×18)+9600

⇒24P=18P=9600

⇒24P−18P=9600

⇒P=

6

9600

=1600

Hence the sum is Rs.1600.

Hence the correct answer is 1600.

Answer 2

Answer:

Let P be the principal sum. ... Hence the sum is Rs. 1600. Hence the correct answer is 1600.