Reet invested an amount of Rs A for 2 years at 12% compound interest ...
Solution:
Let the amount invested by Reet be Rs A.
According to the question,
Reet's investment = Rs A
Rate of interest = 12%
Time period = 2 years
Simple Interest earned by Sonali = Compound Interest earned by Reet
Amount invested by Sonali = Rs (A + 1500)
Rate of interest = 8%
Time period = 3 years
Now, we will calculate the compound interest earned by Reet.
Compound Interest = P[(1 + R/100)^n - 1]
Where,
P = Principle amount
R = Rate of interest
n = Time period
Compound Interest = A[(1 + 12/100)^2 - 1]
Compound Interest = A[(28/25) - 1]
Compound Interest = A[3/25]
Compound Interest = 3A/25
Now, we will calculate the simple interest earned by Sonali.
Simple Interest = (P x R x T)/100
Where,
P = Principle amount
R = Rate of interest
T = Time period
Simple Interest = (A + 1500) x 8 x 3/100
Simple Interest = (24A + 36000)/100
Simple Interest = 6A/25 + 1440
According to the question,
Compound Interest earned by Reet = Simple Interest earned by Sonali
3A/25 = 6A/25 + 1440
3A/25 - 6A/25 = 1440
-3A/25 = 1440
A = -1440 x 25/3
A = -12000
Since the amount invested cannot be negative, we will reject this value of A.
So, the correct value of A will be the one which satisfies all the given conditions.
Let us assume that A = Rs 25000.
Compound Interest earned by Reet = 3A/25
Compound Interest earned by Reet = 3 x 25000/25
Compound Interest earned by Reet = Rs 3000
Simple Interest earned by Sonali = 6A/25 + 1440
Simple Interest earned by Sonali = 6 x 25000/25 + 1440
Simple Interest earned by Sonali = Rs 3600
Since both the interests are equal, the amount invested by Reet is Rs 25000, which is given in option B.
Reet invested an amount of Rs A for 2 years at 12% compound interest ...
According to the question,
144A = 3600000
A = 25000
Amount invested by Reet = Rs 25000
Hence, the correct option is (B).