The difference between simple and compound interests compounded annually on a certain sum of money for 2 years at 9 % per anmum is Rs . 405 The sum is

A tap can fill a Tank in 16 hours. Due to a hole in its base it is filled in 24 hours, If tank is full then in how many hours it will be empty through the hole. 

The average of 8 readings is 24.3, out of which the average of first two is 18.5 and that of next three is 21.2. If the sixth reading is 3 less than seventh and 8 less than eight, what is the sixth reading? 

An alloy contains zinc, copper and tin in the ratio 2:3:1 and an other contains copper, tin and lead in the ratio 5:4:3. If equal weights of both alloys are melted together to form a third alloy, then the weight of lead per kg in the new alloy will be.

Find out the H.C.F of 306, 204 and 136.

A motorboat, whose speed is 45 km./hr. in still water goes 180 km. downstream and comes back in a total of 9 hours. The speed of the stream (in km/hr.) is-

5 number whose average is 76, the first is 3/7 times the sum of other 4. the first number is: