A.
Kayleen left home at noon and drove to boston. she got there at 4:00.if boston is about 280 miles away, what was kayleens average speed.

b. Elijah was also driving to Boston, but she left from outside of the city and was already 40 miles closer than Kayleen was when she started. She also left at noon and got there at 4:00. What was her average speed?

, 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