How long will it take for an amount to become 5 times of itself at 15% per annum simple interest?

How much time will it take for an amount of Rs. 450 to yield Rs. 81 as interest at 4.5% per annum of simple interest?

Answer: Option B

Explanation:

so 4/4.5=4 (given ans)but

4/4.5=0.8888

So my doubt is how the ans was 4 years? can anyone explain me clearly?

So, lets dived them as 1800/450 = 4 years.

Bcoz if you want to convert decimal into number just put that much zeros same as above number here in 4.5 we convert it into 450 so just put two zeros above also bcoz from fraction point we increase 2 no. so 2 zeros are der.

Best of luck

We know that I= PTR/100
He gave I=81, p=450, R= 4.5 we have to find time (T)=?
T=100*I/PR
(100*81)/(4.5*450)= 8100/2025= 4 years got it.

given data is:
S.I=81.
P=450.
R=4.5.

Formula is N=100*si/p*r.
=100*81/450*4.5.
=8100/2025.
=4.

N=4 years.

So to get 81 we have to perform (81/20.25) = 4.

We know that amount = principle(or)sum + s.i.

So the ans might be 4.5.

But here sum (or) principle is not given but he say that Rs450 to yield means we have to keep in mind that the amount never yield (produce) interest only the principle will (produce) interest; so the given amount is principle only.

As we know : SI = P*R*T/100.
: T = S.I*100/P*R.
i.e: 81*100/450*405 = 4 yr.

4% of 450 is. 18.
0.5% of 450 is half the 1% 2.25.

Total 4.5 p.a. is: 20.25.
For 4 years: 4*20.25== 81.

S.I = 81, P = 450, R = 4.5.

T = S.I*100/P*R.

T = 81*100/450*4.5 (Cancel 100/450 with 5 and 81 with 9).

T = 9*2/4.5.
T = 18/4.5 => 180/45.

T = 4 Years.

450*45*4/100*10.

So the answer came to the 81 rs.

That amount we shown in question so answer is true.

T = S.I*100/P*R.

T = 81*100*10/450*45 (Cancel 100/450 with 5 and 81 AND 45 CANCEL WITH 9 AND 45 AND 10 CANCEL WITH 5).

T = 9*2*2/9.
T = 36/9.
T = 4 Years.

100*S.I = p*t*r.

100*S.I/p*r = t.

Here p = 450, S.I = 81, r = 4.5 substitute above we get answer.

The I is an interest which had paid for using someone's money whereas p is the principal or sum which is the amount you borrowed from someone.

1% = 4.5 Rs.

4% = 18.00 Rs.

0.5% = 2.25 Rs.

So 4.5% = 20.25 Rs.

Hence 20.25 * 4 = 81 Rs.

Ans: 4 years.

Then time =100 * 81/450 * 4.5,
= 2 * 9/4.5,
= 18/4.5,
= 18 * 10/45,
= 18 * 2/9,
= 2 * 2,
= 4 years.

We know si=PRT/100.
Therefore T=si*100/P*R,
=81*100/450*4.5,
=81*10/45*4.5,
=81*2/9*4.5,
=9*2/4.5,
=18/4.5,
=4.

The steps you had done is actually like this,
=(100x81)/(450x4.5)
=(2x81)/(9x4.5)
=(2x9)/(1x4.5)
=4.

You hav taken
=(2x2)/(4.5)
bt actually 81/9 is 9 not 2.

To find time 81/18 = 4.5.

We know that S.I=PTR/100.
A.(450*3.5*4.5) ÷ 100=70.8,
B.(450*4*4.5) ÷ 100=81(ans) means 4years,
C.(450*4.5*4.5) ÷ 100=91.1
D.(450*5*4.5)÷100=1001.2.

t = (100*81)/(450*4.5),
= 8100/{450*45/10},
= 8100/2025,
= 4.

Now, the interest amount 81.

81/20.25===>4years.

Please explain me to remove the decimal point.

P is principle right. A is total amount. How it will come as years?

Amount, the principal is the money which we lend for example I want to take 50 rupees from the bank so that will be loan or pricipal after 1 year the bank also want s s profit so they give a rate of interest for eg 2 pc so simple interest is prt/100 which will be 1 so at the end of the year they will have to give bank 501 rupees which is the amount.

So a=si + p.

So, We Get T = S.I *100/P*R
T = 81 * 100/450 * 4.5,
So, T = 4 YEARS.

PRINCIPAL = AMOUNT-SI (OR) SI*100/R*T.

S.I=(PxRxT)/100 ---------------> (1)
where s.i =simple interest
R=rate %
P=sum or principal
T=year.

Amount = principal + simple interest
A = P + S.I ------------> (2).

From the question.
S.I = 81
Amount =450
R=4,5% P=?
A = P + S.I -----> (2)
450 = P + 81
p=450 - 81 =369 i.e :- P =369

And now using eq(1)

S.I =(P x R xT) / 100.............(1)
81=(369 x 4.5 x T) / 100
T= (81 x 100)/369 x 4.5
T= 4 years.

81*100= 450 * 4.5 * time.
8100 = 2025 * time.
Time = 8100/2025 = 4 year.