Question

Rs 1800 is given at 20% per annum Sl while Rs (1800-P) is given at30% per annum Cl.if the difference between both
interests at the end of two years is 315. find P​

Answer 1

Answer:

S.I on rs 1800=( 1800*2*20)/100=720

C.I =(1800-P)( 1+0.3)^2-(1800-P)

=1242-0.69P=720+315=1035

0.69 P=207

P=207/0.69= rs 300

Answer 2

Answer:

P= 300

Explanation:

Case I

Principal= Rs. 1800     Rate= 20%     Time= 2yrs

Simple Interest = (Principle*Rate*Time) / 100

Here, Simple Interest = $\frac{1800*20*2}{100}$ = Rs. 720

Case II

Principal: 1800-P     Rate: 30%     Time: 2yrs

While calculating Compound Interest

Amount= Principle (1+$\frac{Rate}{100}$)

Here, Amount= $\frac{169}{100}$*( 1800-P )

Compound Interest = Amount- Principle=  (69/100) * 1800-P

ATQ

CI₂ - SI₁ = 315

$\frac{69}{100}$ *(1800-P)- 720 = 315

P = 300