Problems on Simple Interest

Q21. On a certain sum, the simple interest at the end of 10½ years becomes 3/4 of the sum. What is the rate percent per annum ?

 (a) 7 1 % 7
 (b) 5 1 % 3
 (c) 3 1 % 7
 (d) 7 3 % 7

Q22. If the annual rate of simple interest increases from 10% to 12½%, a man's annual income increases by Rs. 1250. The Principal is
(a) 5000
(b) 15000
(c) 30000
(d) 50000

Q23. Rs. 3000 amount to Rs. 3600 in 5 years at simple interest. If the interest rate were increased by 3%, it would amount to how much ?
(a) 3775
(b) 3820
(c) 4010
(d) 4050

Q24. A certain sum of money becomes three times of itself in 10 years at simple interest. In how many years does it become double of itself at the same rate ?
(a) 3 years
(b) 4 years
(c) 5 years
(d) 7 years

Q25. If the simple interest on a certain sum of money for 18 months at 6½ % per annum exceeds the simple interest on the same sum for 8 months at 10½ % per annum by Rs. 33. The sum is
(a) Rs 260
(b) Rs 275
(c) Rs 300
(d) Rs 350

Q26. Simple interest on a certain sum at a certain annual rate of interest is 25/16 of the sum. If the numbers representing rate percent and time in years be equal, then rate percent per annum is
(a) 12½ %
(b) 13¼ %
(c) 14½ %
(d) 15¾ %

Q27. The simple interest on a sum for 4 years is two-fifth of the sum. The rate percent per annum is
(a) 7 %
(b) 9 %
(c) 10 %
(d) 12 %

Q28. Rs. 2000 is invested at 5 % per annum simple interest. If the interest is added to the principal after every 10 years, the amount will become Rs. 4000 after ?

 (a) 13 3 years 7
 (b) 16 2 years 3
 (c) 17 2 years 3
 (d) 19 5 years 7

Q29. A sum of Rs. 10 is lent to be returned in 11 monthly instalments of Rs 1 each, interest being simple. The rate of interest is

 (a) 8 3 % 7
 (b) 11 2 % 5
 (c) 19 2 % 7
 (d) 21 9 % 11

Q30. X, Y, Z are three sums of money such that Y is the simple interest on X and Z in the simple interest on y for the same time and rate. Which of the following is correct ?
(a) y2 = xz
(b) y = xz
(c) x = yz
(d) z2 = xy

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