Aptitude - Simple Interest - Discussion

@All.

The question is a little tricky.

[many years as the rate of interest] this means;
[Many years= rates of interest].

Therefore we can take anyone as a,x,t,n,r etc.

Years=rate of interest= X ----------> Eqn.(1)

We can also take the T alternative of X.

Then we solve the ans.
S.I=PTR/100.

We didn't know the value of T&R so move to the left side.
TR=(S.I * 100)/P
From Eqn. 1 we know that T&R are the same.
X*X=(S.I*100)/P.

P=principal= sum=1200.
S.I=Simple interest=432.

X^2=(432*100)/1200,
X^2=43200/1200,
X^2=432/12,
X^2=36.
X=√36.
X=6.

Friends, here `as many years as the rate of interest` means
* If you pay Loan Amount + Interest in 2 years(T) then the interest rate should be 2%(R)
* If you pay Loan Amount + Interest in 3 years(T) then the interest rate should be 3%(R)
* If you pay Loan Amount + Interest in 5 years(T) then the interest rate should be 5%(R) and so on

That's the reason, they took R = T and option wise 6 is satisfying the above criteria.

Because 6%(432) = RS.72 needs to pay per year as interest and for 6 years it will be 6 * 72 = RS.432.

So the rate of interest is 6 and years also 6.

Hai friends
Actually reena took sum of Rs.1200 ie P=1200 and paid simple interest of Rs.432
We are asked to find the rate ie R
It is given that, simple interest for as many years as the rate of interest. this line mean that T=R.
Or
you can asuume R & T to some other variable also ie R=T=x

formulato be used is SI=PRT/100
432=1200*R*R/100 (Here i have used T=R)
43200=1200 R square
Rsquare=43200/1200
Rsquare=36
R=6
Hope understand... Goood night

If Reena took Rs. 1200.

SI = P * R * T/100.

She paid of Rs. 432 at the end of the loan period.
Here, rate of interest is directly proportional to time.
P= 1200
SI= 432
R= ?
T=R

Therefore , SI = P * R * T/100.
432= 1200 * R * T=R/100,
432=1200 * R * R/100,
432=1200 * R^2/100,
432= 12 * R^2,
432/12 = R^2,
36 = R^2,

OR
R^ = 36.

Therefore, R = 6 Answer.

If considered, the interest rate = 3.6%.

Then one year interest is = 1200 x 3.6% = 43.2/-.

As per the simple interest rule he paid interest for 10 years = 43.2 x 10 years = 432.

How 3.6% interest is not correct answer please explpain, because in the question there is not mention of how many years he paid interest rs. 432?

Please explain.

Principal = Rs.1200.
Interest = Rs.432.
Rate of interest = x%p.a.
Given the rate of interest=time duration = x.
A = P+I = Rs.1200 + Rs.432 = Rs.1632
A = P[1+(R*T/100)]
1632 = 1200[1+(x*x/100)]
1632 = 1200[1+(x^2/100)]
1632 = 1200/100(x^2+100)
1632 = 12(x^2+100)
136-100 = x^2.
36 = x^2.
x = 6.
Rate of interest = 6%p.a.

Here they given simple interest for as many years as the rate of interest.

So time =rate of interest so we take them as y.
They given our principal is Rs.1200,
S.I= P*T*R/100.
Here S.I=R.s 432,
Here Time=rate of interest,
432=1200*y*y/100.
432=12*y*y,
432\12=y*y,
y*y=36,
So y=6.
So Rate of interest =6%.

But Why we took R two times in this Solution..

We can Take Like R=Rate of Interest and T=Time

the Formula is SI=PRT/100

In this Formula if We take 1 year then the ans will be 36 instead of 6.

Plz Give me Proper Solution for my biggest Confusion..As Soon As

The simple interest for as many years as the rate of interest means;
Let the rate of interest is 12% then the period is 12 years.
so, principle amount(p) = 1200
SI = 432
r = r.
t = r.
SI = ptr/100.
432 = 1200 * r * r/100.
r^2 = 36,
r = 6.

Principal always 100%.
The value of principal = 1200.
SI value = 432.
Rate% * no.of year = SI%.
100% = 1200.
? = 432.

Only divide the same row or the same column. Cross only for multiplication.
Then, R = 6.