math
posted by terry .
a card is picked from a pack containing 52 cards . it is then replaced and a second card is picked. Find the probability that
a)both cards are the seven of diamonds,
b)the first card is a heart and the second a spade.
c)one card is from a black suit and other is from a
red suit
d) at least one card is a queen

I will do two:
b) Pr= 13/52 * 13/52
d)Pr(one a queen)= pr(two queens)+pr(one queen)
Pr(QQ)+Pr(QN)+Pr(NQ)
4/52*4/52 + 4/52*48/52 + 4/52*48/52
= (16+2*4*48)/52*52=.148 check it.