Day 1 Day 2 Day 3 Day 4 Day 5 17 21 25 29 33 The table shows how the number of sit-ups Marla does each day has changed over time. At this rate, how many sit-ups will she do on Day 12? Explain your steps in solving this problem.
To find out how many sit-ups Marla will do on Day 12, we first need to determine the pattern or trend in the data provided.
From the given data, we see that the number of sit-ups Marla does each day is increasing by 4. This means that the increase in sit-ups is constant.
To find out how many sit-ups she will do on Day 12, we can use the formula for arithmetic sequences:
an = a1 + (n-1)d
where:
an = the nth term (number of sit-ups on Day 12)
a1 = the first term (number of sit-ups on Day 1)
d = the common difference (increase in sit-ups each day)
n = the term number we want to find (Day 12)
Plugging in the values we have:
a1 = 17
d = 4
n = 12
an = 17 + (12-1) * 4
an = 17 + 11 * 4
an = 17 + 44
an = 61
Therefore, Marla will do 61 sit-ups on Day 12.