Aptitude - Simple Interest
6.
A sum of money amounts to Rs. 2240 in 2 years and to Rs. 2600 in 5 years at simple interest. The sum is :
Answer
S.I. for 3 years = Rs. (2600 − 2240) = Rs. 360
S.I. for 1 year = Rs. 120
S.I. for 2 years = Rs. 120 x 2 = Rs. 240
Sum = Rs. (2240 − 240) = Rs. 2000
Answer :
Option BExplanation :
S.I. for 3 years = Rs. (2600 − 2240) = Rs. 360
S.I. for 1 year = Rs. 120
S.I. for 2 years = Rs. 120 x 2 = Rs. 240
Sum = Rs. (2240 − 240) = Rs. 2000
7.
In how many years, a sum will be thrice of it at the rate of 10% per annum ?
Answer
Let the sum be Rs. x. Then, S.I. = Rs. (3x − x) = Rs. 2x
x x 10 x t100 
= 2x
⇒ t = 20 years
Answer :
Option BExplanation :
Let the sum be Rs. x. Then, S.I. = Rs. (3x − x) = Rs. 2x
x x 10 x t100 = 2x⇒ t = 20 years
8.
A borrows Rs. 8000 at 12% p.a. simple interest and B borrows Rs. 9100 at 10% p.a. simple interest. In how many years will their amounts of debts be equal ?
Answer
Let the required time be t years. Then,
8000 + 8000 x 12 x t = 9100 + 9100 x 10 x t ⇒ 8000 + 960t = 9100 + 910t
⇒ 50t = 1100 ⇒ t = 22 years
Answer :
Option CExplanation :
Let the required time be t years. Then,
8000 + 8000 x 12 x t = 9100 + 9100 x 10 x t ⇒ 8000 + 960t = 9100 + 910t
⇒ 50t = 1100 ⇒ t = 22 years
9.
A sum of Rs. 600 amounts to Rs. 720 in 4 years. What will it amount to if the rate of interest is increased by 2% ?
Answer
P = Rs. 600, S.I. = Rs. (720 − 600) = Rs. 120, T = 4 years
Rate = 100 x 120600 x 4 % = 5% p.a.
New rate = 7% p.a., P = Rs. 600 and T = 4 years.
S.I. = Rs. 600 x 7 x 4100 = Rs. 168
Required amount = Rs. (600 + 168) = Rs. 768
Answer :
Option CExplanation :
P = Rs. 600, S.I. = Rs. (720 − 600) = Rs. 120, T = 4 years
Rate =
100 x 120600 x 4 % = 5% p.a.New rate = 7% p.a., P = Rs. 600 and T = 4 years.
S.I. = Rs.
600 x 7 x 4100 = Rs. 168 Required amount = Rs. (600 + 168) = Rs. 768
10.
The simple interest on a sum for 5 years is two-fifth of the sum. The rate percent per annum is :
Answer
Let the sum be Rs. x. Then , S.I. = Rs. 2x5
Rate = 100 x S.I.P x T = 100 x 2x5 x 1x x 15 % p.a. = 8% p.a.
Answer :
Option BExplanation :
Let the sum be Rs. x. Then , S.I. = Rs. 2x5
Rate = 100 x S.I.P x T =
100 x 2x5 x 1x x 15 % p.a. = 8% p.a. Jump to page number :