Answer:
They add up to 720 degrees
Let's say that x represents hours that Elizabeth volunteers over 1 week. Katie volunteers x+3 and Siobhan x-1 hours per week. The equation that arises from condition in text is:
3*(x+3) = 3*(x + x-1)
x+3 = 2*x - 1
2*x - x= 3+1
x=4.
Elizabeth volunteers 7 hours
Katie volunteers 4 hours
Siobhan volunteers 3 hours
Set up a proportion. take 3/6 = 20/x
Cross multiply 3 * x = 6 * 20
Simplify 3x = 120
Divide by 3 x = 40
So the denominator of the bottom fraction is 40
