Aptitude - Simple Interest - Discussion

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.

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.

S.I = P * R * T/100.
1200 * R * T/100 = 432.
Let us calculate for one year;
1200 * r * 1 = 432 * 100,
r = 432 * 100/1200 * 1,
r = 6.

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.

How? Please explain to me the answer.

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 Amount * 100 = principle * time* rate is a simple formula for si.
432*100 = 1200*t*r.
43200/1200 = t*r.
36 = t*r.
Here t=r given;
So r=6 and t=6.

1200 * R * R/100 = 432.
12R * R = 432,
R * R = 432/12,
R * R = 36,
R = 36/2,
R = 6.

I am not getting this one. Please clarify the formula, clearly.

@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.