Question

Andy sometimes gets a lift to and from college. When he does not get a lift he walks. The probability that
he gets a lift to college is 0.4. the probability that he walks home from college is 0.7. Geting to college and
getting home from college are independent events.
draw a tree diagram

Answer 1

Calculate the probability that Andy gets
a lift to college and walks home from
ccllege.

Answer 2

Calculate the probability that Andy does
not get a lift to or from college

Answer 3

Here is the tree diagram for Andy getting a lift to and from college:

/ \
Lift (0.4) Walk (0.6)
/ \
Home (0.3) Lift (0.7)
/ \
Home (0.7) Walk (0.3)

Answer 4

To calculate the probability that Andy gets a lift to college and walks home from college, we need to multiply the probabilities of each event happening:

P(gets a lift to college) = 0.4
P(walks home from college) = 0.7

P(gets a lift to college and walks home from college) = P(gets a lift to college) * P(walks home from college)
= 0.4 * 0.7
= 0.28

Therefore, the probability that Andy gets a lift to college and walks home from college is 0.28 or 28%.

Answer 5

To calculate the probability that Andy does not get a lift to or from college, we need to find the complement of the event that he gets a lift to college or walks home from college.

P(Andy does not get a lift to college or walks home from college) = 1 - P(Andy gets a lift to college or walks home from college)

P(Andy gets a lift to college or walks home from college) = P(gets a lift to college) + P(walks home from college) - P(gets a lift to college and walks home from college)
= 0.4 + 0.7 - 0.28
= 0.82

P(Andy does not get a lift to or from college) = 1 - 0.82
= 0.18

Therefore, the probability that Andy does not get a lift to or from college is 0.18 or 18%.