Posted by Lacey on .
I just have one more question.
I need to find the equation for the following word problem: a group of yeasts cells grows by 75% every 3 hours. At 9 a.m., there are 200 yeast cells.
Write an equation that models the number of yeast cells after 9 a.m.
So far I've worked out that C=200(1.75)^ , but my book says that it should be ^t/3, I suppose the /3 refers to the 'every three hours' bit, but, I don't understand why. Can someone please help me understand this?

Math  last one 
bobpursley,
the rate is 1.74 each three hours. THe way you write it then, giving t in hours, is just t/3. At t=3hrs, it give you
200*(1.75)^(3/3) or 200*1.75 
Math  last one 
Lacey,
yes, but why is it t/3?