Aptitude : Simple Interest

(6) A sum of Rs. 5000 is lent out in two parts, one at 5% and another at 6%. If the total annual interest is Rs. 260, find the amount lent at 5%.

• (a) Rupees
• (b) Rupees
• (c)4000 Rupees
• (d) Rupees

Answer

Correct Answer : (c) 4000 Rupees
Let x be the amount lent at 5%.
The amount lent at 6% is 5000 – x.
The interest earned on x at 5% is 0.05x.
The interest earned on 5000 – x at 6% is 0.06(5000 – x).
The total interest earned is 0.05x + 0.06(5000 – x) = 260.
Solving for x, we get x = 4000.
Therefore, the amount lent at 5% is Rs. 4000.

(7) A man invested Rs. 4455 in a bank at 8% p.a. simple interest. After how many years will the amount in the account be Rs. 5334?

• (a)2.47 Years
• (b)2.88 Years
• (c)3.45 Years
• (d)3.99 Years

Answer

Correct Answer : (a) 2.47 Years
Simple Interest = (principal amount * rate of interest * time period) / 100
We know that the principal amount is Rs. 4455, the rate of interest is 8%, and the simple interest is Rs. 889 (5334 – 4455).
889 = (4455 * 8 * time period) / 100
time period = (889 * 100) / (4455 * 8)
time period = 2.47 years
Therefore, the amount in the account will be Rs. 5334 after 2.47 years

(8) If a man lends Rs. 7500 at 5% p.a. simple interest and the same amount at 6% p.a. simple interest, what will be the total interest earned after 2 years?

• (a)1500 Rupees
• (b)985 Rupees
• (c)1650 Rupees
• (d)1250 Rupees

Answer

Correct Answer : (c) 1650 Rupees
To calculate the total interest earned after 2 years, we need to calculate the interest earned on each amount separately and then add them together.
Let’s calculate the interest earned on Rs. 7500 at 5% p.a. simple interest for 2 years:
Interest_1 = (Principal * Rate * Time) / 100
Interest_1 = (7500 * 5 * 2) / 100
Interest_1 = Rs. 750
Now, let’s calculate the interest earned on the same amount of Rs. 7500 at 6% p.a. simple interest for 2 years:
Interest_2 = (Principal * Rate * Time) / 100
Interest_2 = (7500 * 6 * 2) / 100
Interest_2 = Rs. 900
Finally, we can find the total interest earned by adding the two interest amounts:
Total_interest = Interest_1 + Interest_2
Total_interest = Rs. 750 + Rs. 900
Total_interest = Rs. 1650
Therefore, the total interest earned after 2 years when lending Rs. 7500 at 5% p.a. simple interest and the same amount at 6% p.a. simple interest would be Rs. 1650.

(9) How much time will it take for an amount of Rs. 450 to yield Rs. 81 as interest at 4.5% per annum?

• (a)4.5 Percentage per Annum
• (b)6.5 Percentage per Annum
• (c)7.5 Percentage per Annum
• (d)9.5 Percentage per Annum

Answer

Correct Answer : (a) 4.5 Percentage per Annum
To find the time it will take for an amount of Rs. 450 to yield Rs. 81 as interest at a 4.5% per annum interest rate, we can use the formula for simple interest:
Simple Interest = (Principal × Rate × Time) / 100
Let’s assume the time period is T. We are given:
Principal (P) = Rs. 450
Interest (I) = Rs. 81
Rate (R) = 4.5%
Using the formula for simple interest, we can write the equation:
I = (P × R × T) / 100
Substituting the given values:
81 = (450 × 4.5 × T) / 100
Simplifying the equation:
81 = 20.25T
Dividing both sides by 20.25:
T = 81 / 20.25
T = 4
Therefore, it will take 4 years for an amount of Rs. 450 to yield Rs. 81 as interest at a 4.5% per annum interest rate.

(10) Calculate the principal that will earn Rs. 150 as interest in 3 years at 2.5% per annum.

• (a)1200 Rupees
• (b)1350 Rupees
• (c)2400 Rupees
• (d)3750 Rupees

Answer

Correct Answer : (c) 2400 Rupees
Simple Interest = (principal amount * rate of interest * time period) / 100
We know that the interest is Rs. 150, the rate of interest is 2.5%, and the time period is 3 years.
150 = (principal amount * 2.5 * 3) / 100
principal amount = (150 * 100) / (2.5 * 3)
principal amount = Rs. 2400