Which of the following is largest fraction amongst $$ {5\over8}$$, $$ {3\over7}$$, $$ {2\over9}$$,  $$ {4\over5}$$?

The greatest number less than 1500, which is divisible by both 16 and 18, is:

The present age of father and son are in the ratio 3: 1. After 20 years the ratio becomes 2 : 1 . Find the present age of the father. 

The average weight of a group of 20 boys was calculated to be 89.4 kg and it was later discovered that one weight was misread as 78 kg instead of 87 kg. The correct average weight is 

The ratio of the speeds of the two airplanes is 11: 18. If the first airplane covers a distance of 1650 km in 3 hours, then what is the speed (m / s) of the second airplane?

A batman has a certain average of runs for 12 innings. In the 13^th inning, he scores 96 runs thereby increasing his average by 5 runs. What will be his average after 13^th inning?

Find the value of $$\left({sin 35°\over cos55°} \right)^2+\left({cos55°\over sin 35°} \right)^2 \ -2 sin^{3}30°$$