Doubt

1).if one roots of 5x^2+13x+p be reciprocal of the other then the value of p is

a).-5, b).5, c).1/5, d).-1/5.

2).the number of diagonals in a decagon is

a).30, b).35, c).45, d).none.

3).if n,p,q are in g.p then the expression for p in terms of n & q is-------

a).n/q, b).(nq)^1/2, c).q^2n, d).nq.