Sue either travels by bus or walks when she visits the shops. The probability that she catches the bus TO the shops is 0.4. The probability that she catches the bus FROM the shops is 0.7

a) complete the tree diagram

b) show that the probability that Sue walks at least one way is 0.72

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for

i think its a and d

step-by-step explanation: