Nola hiked down a trail at a steady rate for 10 minutes. Her change in elevation was -170 feet. Then she continued to hike down another 20 minutes at a different rate. Her change in elevation for this part of the hike was -260 feet. During which portion of the hike did she walk down at a faster rate? PLEASE HELP

a and c

step-by-step explanation:

, 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