Four runners started running simultaneously from a point on a circular track. They took 200 seconds, 300 seconds, 360 seconds and 450 seconds to complete one round. After how much time do they meet at the starting point for the first time? 

What will come in place of question mark (?) in the following series?
8, 10, 18, 44, 124, ?

If $$ {x+{1\over 16x}}=1 $$, then $$ {64x^{3}+{1\over 64x^{3}}}$$ will be:

Cost of 24 bats and 32 sticks is Rs 5600. What is the price of 3 bats and 4 sticks?

If 2A = 3B = 7C = 42, then what is the value of A × B ÷ C?

An article is sold at a loss of 20 %. It yields Rs. 60 more when it is sold at a gain of 20 %. The cost price of the article is 

What is the value of x and y in these equations 7x-2y=8 and 3x+4y=18.

Two mobile phones were purchased at the same price. One was sold at a profit of 30 % and the second was sold at a price which was Rs 2500 less than the price at which the first was sold. If the overall profit earned by selling both the mobile phones was 5 %, what was the cost price of one mobile phone?