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

day 1 day 2 day 3 day 4 day 5

17 21 25 29 33

From the given table above, it shows that males sit ups each day has changed over time, and every day, the difference is 4 sit ups. There is a consistent change in her everyday routine. Therefore, since from day 5, her sit ups is 33, day 6 to 12 will be added 4 sit ups per day. Day 6 would be 37, day 7 is 41, day 8 is 45, day 9 is 49, day 10 is 53, day 11 is 57 and therefore, day 12 is 61. So Marla will have 61 sit ups on the 12th day.

The number of situps form an AP with first term (a) = 17 and common difference (d) = 4

Tn = a + (n - 1) d

T12 = 17 + (12 - 1) x 4 = 17 + 11 (4) = 17 + 44 = 61

Therefore, she will do 61 situps on day 12.