Aptitude - Simple Interest - Discussion

What if I take A as 13900-x? Please explain.

@Priya @Swathi @Kasamsetty Deepshika.


Many people asked that what if we take A as 13900-x,

Here the solution is;

Let us take A=(13900-x) , B=x;
S.I of A + S.I of B = 3508.

(13900-x)*14*2 / 100 + x*11*2/100 = 3508,
(13900-x)*28/100 + 22x/100 = 3508,
389200-28x/100 + 22x/100 3508,
389200-28x + 22x = 3508*100,
389200-28x + 22x = 350800,
389200- 350800 = 28x-22x.
38400 = 6x.

x = 38400/6 =>6400.
Therefore we found x which is A.

NOTE:
if we substitute B = (13900-x) we have to subtract x from 13900 to get an answer
Here we took B as x so we find the answer in the first step. (SI of A + SI of B = 3508).

@Priya @Swathi @Kasamsetty Deepshika.

A:14% for 2 years = 28% (In si rate of interest is same for every year i.e. for 2yrs 14 is directly multiplied).

B:11%for 2years = 22%.

28% of principal13900=3892 (interest) but the interest of A+B scheme is given=3508.

i.e 384 extra (3892-3508) =384.

28%~22%=6%.
6%---> 384.
100%---> 6400.

Given,

Time = 2yrs
Total interest earn 2 yrs = 3508.
Interest for A and B is 14% and 11q respectively,
Let Scheme A be X and Scheme B be 13900 - X,
Then; A will be = (X*14*2/100),
B will be = ((13900-X)*11*2/100).

(X*14*2/100)+((13900-X)*11*2/100) = 3508,
(28X/100)+(13900*22-22X/100)=3508,
28X-22X + 305800/100 = 3508,
28X-22X + 305800 = 3508*100,
6X + 305800 = 350800,
6X = 350800 - 305800,
6x = 45000,
X = 45000/6,
X = Rs. 7500.

Substitute x with 7500 in (13900-X).
= 13900-7500.
= Rs. 6400.

Invested amount in Two Scheme 13900.
In scheme A invested ratio 14% and in Scheme B invested ratio 11%.
Simple Interest for 2 years 3508.
Question- B scheme's invested amount .

Answer-

Method-.
PTR/100 + PTR/100( A and B scheme)=3508(SI).
Let's P for A scheme- x
Then P of B scheme - 13900-x.
(You have total 10 mangoes. You give 4 mangoes to A and then rest mangoes which will give to B = Total mangoes(10)- A's mangoes(4)= 6 mangoes for B).


x*2*14/100+(13900-x)*2*11)/100 = 3508.
= 28x/100+(13900-x)*22/100 = 3508.
= 28x/100+{(22*13900)-(22*x)} = 3508.
= 28x/100+(305800)-22x = 3508.
= 28x-22x=350800-305800.
= 6x = 45000.
= x= 4500/6 = 7500(A's investment in 13900).

Then B's investment= 13900 - A's investment.
= 13900-7500= 6400.