Ten boys and twelve girls decide to rent a 16-passenger van and a 6-passenger to drive to a rock concert in a near by city. if the group is distributed between the vehicles, whats the probability that
a) there are no boys in the car
b) steve and susan are both in the van
c) either steven or susan are in the van
d) there are no girls in the car

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.