S = 2d + 13 , where S is the number of situps, d is the number of days, d≥1 , d is an integer.
check:
if d = 1, (first day) , S = 15
if d = 2 (2nd day) , S = 17
yup that works
so if S = 33
33 = 2d + 13
2d = 20
d = 10
We could arrange the equation:
2d + 13 = S
2d = S - 13
d = (S - 13)/2
I really don't know what you mean by "not counting the first day". Why not ?
Jerry started doing sit ups every day. The first day he did 15 sit ups. Every day after that he did 2 more sit ups than he had done the previous day.
Today Jerry did to 33 sit ups. Write an equation that could be solved to find the number of days Jerry has been doing sit ups, not counting the first day.
1 answer
1 answer