In a group of 20 singers and 40 dancers, 20% of the singers are less than 25 years old and 40% of the entire group are under 25 years. What percentage of dancers are under 25 years?

In the figure below, O of the circle is the centre. OA = 3 cm, AC = 3 cm and OM is perpendicular to AC. So the value of ∠ABC will be

What is the ratio of the simple interest earned on a certain amount at the rate of 21% per annum for 8 years to that earned on the same sum at the same rate for 21 years?  

In 3 years ₹ 3000 amounts to ₹ 3993 at x % compound interest, compounded annually. The value of x is 

What is the value of a⁵ × a⁷ ?

Find the value of (cosA - sinA)² + (cosA + sinA)²   -

In circular measure, the value of the angle 11⁰15’ is : 

A work is done by three person A, B and C. A alone takes 10 hours to complete the work but B and C working together takes 4 hours, for the completion of the same work. If all of them worked together and completed 14 times of the work, then how many hours have they worked?