**A certain sum of money triples itself in 5 years at simple interest. In how many years it will be five times?**[SSC CGL 2017] (a) 5 (b) 8 (c) 10 (d) 15**If Mohan deposited the same amount of****`x in a bank at the beginning of successive 3 years and the bank pays a simple interest of 5% per annum, then the amount at his credit at the end of 3rd year will be**[SSC 2015] (a) ` 21x/ 20 (b) ` 861x/ 400 (c) ` 1261 x/400 (d) ` 26481x/ 8000**Out of****`50000, a man lends****` 8000 at 1 5 % 2 per annum simple interest and****`24000 at 6% per annum simple interest He lends the remaining money at a certain rate of interest so that he gets a total annual interest of****`3680. The rate of interest per annum, at which the remaining money is lent, is**(a) 12% (b) 10% (c) 7% (d) 5%**The principal which gives****`1 interest per day at a rate of 5% simple interest per annum is**[SSC CGL 2015] (a) ` 3650 (b) ` 7300 (c) ` 8400 (d) ` 10950**In certain years a sum of money doubles itself at 1 6 % 4 simple interest per annum, then the required time will be**[SSC CGL 2015] (a) 8 years (b) 10years8months (c) 12 years 6month(d) 16 years**The simple interest on rs****7300 from 11 May 1987 to 10 September 1987 (both days included) at 5% per annum is**(a) `123 (b) `136 (c) `212 (d) `223**A man lent****`60000, partly at 5% and the rest at 4% simple interest. The total annual interest is****`2560, the money lent at 4% was**(a) ` 42000 (b) ` 44000 (c) ` 45000 (d) ` 48000**At the rate of simple interest per annum, the interest on a certain sum of money for 10 years will be 2 th 5 part of the amount, then the rate of simple interest is**[SSC CGL 2014, 15] (a) 4.5% (b) 5% (c)6.33% (d) 7%**If x, y, z are three sum of money such that y is the simple interest on x and z is the simple on y for the same time and at the same rate of interest, then we have**[SSC 2013] (a) x**2**= yz (b) y**2**= zx (c) z**2**= xy (d) xyz = 1

10. The simple interest on a certain sum for 8 months at 4% per annum is `129 less than the simple interest on the same sum for 15 months at 5% per annum. The sum is (a) `3600 (b) `2529 (c) `2400 (d) `2580