In a class of 50 students there are 27 girls. The average weight of these girls is 45 kg and average weight of the full class is 49.6 kgs. What is the average weight of the boys of the class?

If then the value of

Simplify : $$ {(7) ^{2} ÷(7^{1\over 2})^{4}}$$

A number if required by 25% becomes 225. By what percent should be increased so that it becomes 375?

What is the angle between the two hands of the clock at 8:24 pm?

What least number must be subtracted from 1936 so that the resulting number when divided by 9, 10 and 15 will leave in each case the same remainder 7? 

A car running at 7/11 of its own speed reached a place in 22 hrs. How much time could be saved if the car would run at its own speed?

A boat goes 15 km in an hour in still water, and takes thrice the time to cover the same distance upstream. The speed of the current (in km / hr) is –