If R:S=3:1 and S:T=1:5, then R:S:T=______.

If t_n = 3^(n+1) , then S_6 - S_5 = __________.

If R = (a^(3)+1)/(a-1) and S = (a^(2) - a+1)/(a+1) , then R + S is:

In Fig. 6.42, if lines PQ and RS intersect at point T, such that /_P R T=40^@, /_R P T=95^@ and /_T S Q=75^@, find /_S Q T .

2.If r+s=t and x=y then the true statement is (A)r+s-x=y-t (B)r+s-t=x+y (C)r+s+x=t+y (D)r+s+t=x-y

In Fig. 6.44, the side QR of PQR is produced to a point S. If the bisectors of /_P Q R and /_P R S meet at point T, then prove that /_Q T R=1/2/_Q P R .