Aptitude - Simple Interest - Discussion

How 45000 will come? Please explain it.

@Phani Kumar.

Can you plz tell me how to take a difference between r1 and r2 (14% - 11%) or (14*2-11*2).

From the question we know 13900 is the amount he invested.
Let assume, 'x' be the amount invested on A.
so 13900-x be the amount B have

SI=PNR/100.
Case of A:
for 2 years, as per the question.
SI1=x*2*14/100
Similarly
Case of B:
for 2 years
SI2=(13900-x)*2*11/100

its given that the total amount of simple interest is 3508
ie,SI1+SI2=3508

substituting the above two equations
Then, x x 14 x 2 /100 + (13900 - x) x 11 x 2/100 = 3508
28x - 22x = 350800 - (13900 x 22)
6x = 45000
x = 7500.
So, sum invested in Scheme B = Rs. (13900 - 7500) = Rs. 6400.

The answer can be 6400 or 7500.

It is not necessary that A will invest X and B will invest the difference.

350800 - (13900 x 22) =45000 How its came?

Let's assume any answer between option, suppose 6400,
and total amount is given 13900 so, 13900-6400=7500 so we got two values of principle(p),
we know formula i,e SI= P*R*T/100.
so put value...SI=7500*14*2/100=2100 AND SI=6400*11*2/100=1408 and addition of this is =3508. So, A invest 7500 AND B invest 6400.

@ Aditi.

Nice explanation.

they asked for scheme B so we shld take x=13900-y instead of y=13900-x.

Simple interest for two year 3508, therefore simple interest for one year will be1754
x+y=13900 ---> Equation (1).

14x+11y=175400 ---> equation 2.
To solve the equation we are multiplying the equation 1 by 14.
14x+14y=194600 ---> equation 1 after multiply by 14.
14x+11y=175400.

After subtracting the equation we will get.
3y = 19200,
Y = 6400.

Why the amount invested in the scheme a should be taken as x and in scheme b should be taken as 13900-x, as both amounts are part of 13900?

I am confused with the following stem.
28x + 305800 - 22x = 3808 * 100.

Where did the other denomination (ie 100) gone?