For what value of r, ``^8P_r` is maximum?

For which values of r, .^nC_r=^nP_r ?

What is the height at which the value of g is the same as at a depth of R/2?

Write down the greatest value of ^20C_r and ^19C_r

Find the value of n if ""^54P_(r+3)=6840 xx ""^54P_(r+6)

A body is projected so that it has maximum range R. What is the maximum height reached during the flight.

In a Wheatstone bridge the ratio arm P and Q are approximately equal. When R = 500Omega the bridge is balanced. On interchanging P and Q the value of R is 505Omega . Calculate the value of S.

If A is a certain event, then what is the value of P(A) + P(A^C) ?

At S.T.P. the value of R is ----------- Latm K^(-1) mol^(-1)

Find the values of n and r if ""^nP_r=336,""^nC_r=56 .