Simple interest
- A person invests ₹ 12,000 as fixed deposit at a bank at the rate of 10% per annum simple interest. But due to some pressing needs he has to withdraw the entire money after 3 years, for which the bank allowed him a lower rate of interest. If he gets ₹ 3,320 less than what he would have got at the end of 5 years, the rate of interest allowed by the bank is
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As we know that ,
SI = P × R × T 100 S.I. after five years = Principal × Time × Rate 100 S.I. after five years = 12000 × 5 × 10 = ₹ 6000 100
Interest earned = ₹ (6000 – 3320) = ₹ 2680∴ Rate = SI × 100 Principal × Time
Correct Option: B
As we know that ,
SI = P × R × T 100 S.I. after five years = Principal × Time × Rate 100 S.I. after five years = 12000 × 5 × 10 = ₹ 6000 100
Interest earned = ₹ (6000 – 3320) = ₹ 2680∴ Rate = SI × 100 Principal × Time Rate = 2680 × 100 = 67 12000 × 3 9 Rate = 7 4 % 9
- A sum of Rs. 800 becomes Rs. 956 in 3 years at a certain rate of simple interest. If the rate of interest is increased by 4%, what amount will the same sum become in 3 years ?
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According to question ,
S.I. = Amount - Principal = 956 – 800 = Rs. 156∴ Rate = Interest × 100 Principal × Time Rate = 156 × 100 = 6.5% 800 × 3
New rate = (6.5 + 4)% = 10.5%S.I = Principal × Time × Rate 100
Correct Option: C
According to question ,
S.I. = Amount - Principal = 956 – 800 = Rs. 156∴ Rate = Interest × 100 Principal × Time Rate = 156 × 100 = 6.5% 800 × 3
New rate = (6.5 + 4)% = 10.5%S.I = Principal × Time × Rate 100 SI = 800 × 3 × 10.50 = Rs. 252 100
∴ Amount = Principal + SI = Rs.(800 + 252) = Rs.1052
- The rate of simple interest per annum of bank being decreased
The sum deposited at the bank wasfrom 5% to 3 1 % the annual income of a person from interest was less by Rs. 105. 2
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Let Amount deposited in bank = Rs. p
Difference of rates = 5 – 7 2 = 3 % per annum 2 SI = Principal × Time × Rate 100 SI = p × 1 × 3 = 105 100 × 2
Correct Option: D
Let Amount deposited in bank = Rs. p
Difference of rates = 5 – 7 2 = 3 % per annum 2 SI = Principal × Time × Rate 100 SI = p × 1 × 3 = 105 100 × 2 p = 105 × 200 = Rs. 7000 3
- Ratio of the principal and the amount after 1 year is 10 : 12. Then the rate of interest per annum is :
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As per the given in question ,
Principal = 10 Amount 12 Amount = Principal + interest = 12 Principal Principal 10 ⇒ 1 + Interest = 12 Principal 10 ⇒ Interest = 2 = 1 Principal 10 5
Correct Option: D
As per the given in question ,
Principal = 10 Amount 12 Amount = Principal + interest = 12 Principal Principal 10 ⇒ 1 + Interest = 12 Principal 10 ⇒ Interest = 2 = 1 Principal 10 5 ∴ Rate = 1 × 100 = 20% 5
- If Rahim deposited the same amount of Rs. x in a bank at the beginning of successive 3 years and the bank pays simple interest of 5% per annum, then the amount at his credit at the end of 3rd year will be :
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We can find SI with the help of given formula ,
S.I. after 1 yearS.I = Principal × Time × Rate 100 SI = x × 5 100 SI = Rs. x 20 Principal for 2nd year = Rs. 
2x + x 
= Rs. 41x 20 20 S.I. after second year = Rs. 41x × 5 20 100 S.I. after second year = Rs. 41x 400 Principal for third year = Rs. 3x + 41x 400 Principal for third year = Rs. 1200x + 41x 400 Principal for third year = Rs. 1241x 400 ∴ S.I. after 3rd year = Rs. 1241x × 5 400 100 S.I. after 3rd year = Rs. 1241x 8000 ∴ Required amount = Rs. 3x + 1241x 8000
Correct Option: E
We can find SI with the help of given formula ,
S.I. after 1 yearS.I = Principal × Time × Rate 100 SI = x × 5 100 SI = Rs. x 20 Principal for 2nd year = Rs. 2x + x = Rs. 41x 20 20 S.I. after second year = Rs. 41x × 5 20 100 S.I. after second year = Rs. 41x 400 Principal for third year = Rs. 3x + 41x 400 Principal for third year = Rs. 1200x + 41x 400 Principal for third year = Rs. 1241x 400 ∴ S.I. after 3rd year = Rs. 1241x × 5 400 100 S.I. after 3rd year = Rs. 1241x 8000 ∴ Required amount = Rs. 3x + 1241x 8000 Required amount = Rs. 24000x + 1241x 8000 ∴ Required amount = Rs. 25241x 8000
