Question

Ainsley has decided to begin a 5-day sit-up challenge where she plans to increase the number of sit-ups completed each consecutive day by the same amount to gradually build up her core muscle strength.

After talking with a friend who already began the challenge, she's aware that she needs to complete 20 sit-ups on Day 1 of the challenge and will complete 36 sit-ups on the last day, Day 5.

Answer 1

Step-by-step explanation:

this progression is an example of an AP

given a=20, l=56, n=5

so,

$l = a + (n - 1)d$

where d is the increase in no. of Sit ups per day

so,

$56 = 20 + (5 - 1)d$

or

$36 = 4d$

or

$d = 9$

so, common diff =d=9

no. of sit-up on day 2

$a + (n - 1)d = 20 + (2 - 1)9$

$= 20 + 9 = 29$

so, no. of sit-up on day 15=20+(15-1)9

=20+126=146

sorry I could not give you the third answer. actually, the pic is blurred. and so, it could not be understood by me.

please mark me as the brainliest