A cistern can be filled by two pipes filling separately in 12 and 16 min respectively. Both pipes are opened together for a certain time but being obstructions, only 7/8 of full quantity water flows through the former and only 5/6 through the latter pipe. The obstructions, however, being suddenly removed, the cistern is filled in 3 minutes from that moment. How long was it obstructions before the full flow began? 

An article is sold at a loss of 40%. The nominal amount of loss is approximately what percentage of the selling price of the article?

The least number which must be subtracted from 2361 to make it a perfect square is

A and B run a 5 km race on a round course of 400m. If their speed are in the ratio 5: 4, the number of times, the winner passes the other is

O and C are respectively the orthocentre and the circumcentre of an acute angled triangle POR. The points P and O are joined and produced to meet the side QR at S. If ∠POS=60⁰ and ∠QCR = 130°, then ∠RPS = ?

Solve for x if $$ {x^{a^{3}}}.x^{b^{3}}.x^{3ab(a+b)}=(2^{5})^{25},a+b=5 $$

Direction : What should come in place of the question (?) in the following question.

140% of 450 + 24% of 650 =?

A trader had 2000 kgs of rice. He sold a part of it at 10 % profit and the rest at 16 % profit so that he made a total profit of 14.2%. How much rice (in kg) did he sell at 10 % profit?