Question

If the simple interest on Rs 2000 increases by Rs 40, when the time increases by 4 year. Find the rate per cent per annum.​

Answer 1

Answer:

Case 1:

• Principal (P)= Rs2000
• Let rate of interest = R%
• Time = T years
• Simple Interest(l) =Rs x

We know that,

I=PTR/100

x=2000×T×R/100

100x=2000×T×R−−−(1)

Case 2:

• Principal (P)=Rs 2000
• Rate of interest = (R+2)%
• Time = T years
• Simple Interest = Rs (x+40)

x+40=2000×T×(R+2)/100

⟹100(x+40)=2000RT+4000T

⟹100x+4000=2000RT+4000T

100x=2000RT+4000T−4000−−(2)

Now,

From(1)and(2),

we get

2000RT+4000T-4000=2000RT2000RT+4000T−4000=2000RT

⟹4000T=2000RT−2000RT+4000

⟹4000T=4000

⟹T=4000/4000

⟹T=1

Therefore,

Required time (T) = 1 year

Answer 2

Answer:

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