please help

Can you downsize the image in your Q to make it more readable?

3/4 of the pack  + 1/8 of the pack + 1/10 of the pack totals how much? 

First you have to find a common denominator.  40 will work nicely. 

                                           3/4   =  30 / 40 

                                           1/8   =    5 / 40  

                                           1/10  =   4 / 40  

Add them up.                                  39 / 40  

                                    Vivian used 39 / 40 of the pack. 

_.

Add them up and you'll get the answer.