∆ABC is a right angle triangle BD⊥AC. If AD = 12 cm and DC = 8, then BD = ?

A car can finish a certain journey in 10 hours at a speed of 42 kmph. In order to cover the same distance in 7 hours, the speed of the car (km/h) must be increased by:

The area of a rhombus is 144 square units. The length of one of its diagonals is twice the length of other diagonal. What is the sum of length of its diagonals?

A person lent Rs. 8000 partly at the rate of 5% and partly at the rate of 6% per annum simple interest. The total interest after 2 years is Rs. 820 then in which ratio will Rs. 8000 is to be divided?

Triangle PQR is such that PQ=9 cm, QR=6 cm, PR=7.5 cm and triangle PQR is similar to triangle XYZ. If XY=18 cm, find the value of YZ.

The radii of three concentric circles are in the ratio of 4 : 5 : 7. What is the ratio of the area between the two inner circles to that between the two outer circles?

if $$x=\sqrt {64}+\sqrt {121}-\sqrt {169}$$, the find the value of x²

The average of runs scored by a cricketer in his 99 innings is 99. How many runs will he have to score in his 100th innings so that his average of runs in 100 innings will become 100?