M4maths Previous Puzzles

25 Apr 2022 Simple & Compound Interest

Rajan invested certain amount for 4 years in bank A and received the simple interest Rs. 2800. After that he takes all his amount and invest in bank B for 5 years which offers interest rate double than the bank A. At the end of 5 years, from bank B he receives Rs. 9450 as a simple interest. What was the interest rate that bank A offered to Rajan ?

OPtion

1) 9.75
2) 6.75
3) 8.25
4) 7.50
5) 8.75
6) 10.25
7) 17.50
8) 12.50
9) 10.75
10) None of these

Solution

Let initial Principal=P and rate of bank A = r%
Then, Simple interest for 4 years = P*r*4/100 = 2800
⇒ P*r = 70000
Now, for bank B, Principal amount = (P+2800), Rate=2r%
Simple interest for 5 years = (P+2800)*2r*5/100 = 9450
P*r + 2800r = 94500
70000 + 2800r = 94500
Solving, we get r = 8.75%

Correct Option: 5 Best Solution (2)

Pargat Pal Singh   2 years AGO

If initial amount is x and first rate of interest is y% per annum, then
4xy/100=2800
xy= 70000
In second transaction,
(x+288)*5*2y/100 = 9450
xy+2800y= 94500
Putting value of xy=70000,
2800y= 24500
y=8.75%

Like? Yes (4) | No   

G.S.Kantharao   2 years AGO

P*4*R/100=2800=>PR=70000
(P+2800)*5*2R/100=9450
10PR/100+280R=9450
10*70000/100+280R=9450
280R=9450-7000=2450
Now R=2450/280=8.75%
Intrest in Bank A=8.75%
My option is 5👈

Like? Yes (3) | No