Speed of boat in downstream and upstream are 32km/hr and 23km/hr. Find the speed of current ?

Given that ( 1² +2²+3²+………..+10²)=385, the value of (2²+4²+6²+……20²) is equal to

Answer the following questions

P, Q and R alone can complete a piece of work in 24, 36 and 18 days respectively. P started working, after 2 days R joins with them and Q joins with them after another 2 days, then find the no of days P, Q and R worked together.

A cube has sides that are 4 cm each, and the dimensions of a cuboid are 2cm x 3cm x 4cm. Find the positive difference between the volume of the cube and that of the cuboid.

 If $${\sqrt{7-2}\over\sqrt{7+2}}=a\sqrt{7}+b$$, then the value of a is : 

A dozen pair of socks quoted at ₹ 80 are available at a discount of 10%. How many pairs of socks can be bought for ₹24?

A trader marks his goods at 20% above cost price. If he allows a discount of 5% what is his final profit%?

If $$ {x^2} -4x-1 $$ then the value of $$ {{x^6} -{x^4}+{x^2}-1}\over {x^3}$$ will be