A store sells three brands of cigarettes: $3.15 Star lights, $4.30 Vegas slims, and $5.20 Royal 100's. (Tax included) A man named Smokey walks into the store, and buys 2 packs of cigarettes, one pack for himself and the other pack for a friend. He hands the cashier a $20 note, and is returned a few bills and 3 coins in change (exclude dollars or half dollars). What's the probability, that the man smokes Royal 100's?
Ans: ZERO PROBABILITY
3.15+5.2=8.35 20-8.35=11.65 no way in 3coins
4.3+5.2=9.5 20-9.5=10.5 no way in 3coins
3.15+4.3=7.45 change 20-7.45=12.55 ok in 3coins: 25+25+5=55 - without Royal