In the following figure if OA=10 and AC=16, then OB must be:

The value of $$ cot\ {π\over 20}\ cot{3π\over 20} \cot{5π\over20}\ cot{7π\over 20}\ cot {9π\over20}$$ is:

In the given figure AD ‖ BC, if ∠ABC=72°, then ∠BCD=?

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

A number which, when increased by 123% becomes 3345. The number is—

Find the least number exactly divisible by 12,15,20,27 ?

The  LCM of two numbers is 45 times their HCF. If one of the numbers is 125 and sum of HCF and LCM is 1150. The other numbers is-

The average marks of a student in four subjects is 75. If the student obtained 80 marks in the 5^th subject then the new average is ?