<PRE><B>Question 44136</B>
3/5 + 1/2 + 3/4

3/5 = 12/20 
1/2 = 10/20
3/4 = 15/20


You have to find the common denomonator which is where 20 comes in and becomes the denomonator.  Then 20 divided by 5 is 4 and 4x3=12. 
20 divided by 2 is 10 and 10x1=10.
20 divided by 4 is 5 and 5x3=15.

So now you can add yoru problem. 

12/20 + 10/20 + 15/20 = 37/20.

Now you have to reduce this down as it is an improper fraction.

Divide 37 by 20 and you get 1 with remainder of 17.

So yoru final answer would be 1 17/20 is how long Kristi exercised.</PRE>