For #4 calculate two times the probability of in that order.
A biased spinner has the following scores written on it 1, 2, 3 and 4. Such that the probability that the score is 1 is 0.3 and the prob that the score is 2 is 0.6.
Ben spins the pointer once
1) what is the prob he scores 1 or 2?
Is it 0.3 + 0.6 = 0.9
2) he scores 3 or 4?
Is it 1 - 0.9 = 0.1
Rachel spins the pointer twice
3) What is the prob the score is 1 both time?
Is it 0.3 x 0.3 = 0.09
4) What is the prob the score is 2 exactly once?
NOT SURE HOW TO DO THIS ONE
Yes for all three.
For the other one, it is the probability that she gets a 2 on the first throw and another number on the second throw, OR, she scores another nubmer on the first throw and scores 2 on the second throw.
Try it out!
EDIT: Well... Natasha gave it away...