Answer: D Rs 10 + (Interest on Rs 10 for 11 months) = Rs 11 + (Interest on Re 1 for (10+9 +8 +...+1)) months Or, Rs 10 + interest on Rs 10 for 11 months = Rs 11 + interest of Re 1 for 55 months Or, Rs 10 + interest on Re 1 for 110 months = Rs 11 + interest of Re 1 for 55 months Or, Re 1 = Interest on Re 1 for 55 months 1 = (1*R*55)/(12*100) => R = 240/11
Q. No. 21:
A man earns 6% SI on his deposits in Bank A while he earns 8% simple interest on his deposits in Bank. If the total interest he earns is Rs 1800 in three years on an investment of Rs 9000, what is the amount invested at 6% ?
Answer: B Suppose, the man invests x in 6% and y in 8% x+y = 9000 ............(i) And, 3 (x*6/100 + y*8/100) = 1800 => 3x + 4y = 30,000...........(ii) On solving both the equations we get, x = Rs 6,000.
Q. No. 22:
A certain sum of money is invested at an interest rate of 5% per annum and a second sum, twice as large as the first, is invested at 5.5% per annum. The total amount of interest earned from the two investments together is Rs 1000 per year and the interest is withdrawn every year. The second sum invested is :
Answer: C Let the sum of money be x and 2x. Interest on both the sums = (x*5*1)/100 + (2x*5.5*1)/100 = 16x/100 According to question, 16x/100 = 1000 => x = Rs 6,250 Hence, second sum invested = 2x = Rs 12,500.
Q. No. 23:
The compound interest accrued on an amount of Rs 18000 at the end of three years is Rs 5958. What would be the simple interest accrued on the same amount at the same rate in the same period ?
Answer: B P= Rs 18,000, R = 10%, T = 3 years S.I = (PRT)/100 = 18,000* 10*3/100 = Rs 5400.
Q. No. 24:
Arun borrowed a sum of money from Jayant at the rate of 8% per annum simple interest for the next 4 year, 10% per annum for the next 6 years and 12% per annum for the period beyond 10 year. If he pays a total of Rs 12,160 as interest only at the end of 15 year, how much money did he borrow ?