The average of x numbers is 48. If of the numbers are increased by 51 each and remaining are decreased by 71 each, then what is the new average?

$$ {4\over 5}×[{1\over 2}\ of\ 25]+12÷{3\over 4}-32=?$$

Four pipes P, Q, R and S can fill a cistern in 25, 20, 50 and 40 hours respectively. The pipe Q was opened at 7 pm, P at 9 pm, S at 10 pm and R at 11 pm. When will the cistern be full?

A cylindrical well of depth 21 m with internal radius of 13 m is dug up. The mud, so detained, is spread evenly to form a platform of dimension 52 × 13.2. What is the height of the platform?

Akshita is at Delhi and Rajat is at gurgaon. Started towards each other, if the ratio of their speed be 8 : 13 respectively then what is the ratio of distance covered by A and B respectively till the point of meeting?

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

If the compound interest on a certain sum for 2 years at 4% p.a. is Rs. 102, the simple interest at the same rate of interest for two years would be:

If two numbers are respectively 20% and 50% of a third number, what is the percentage of the first number to the second?