You and a friend have a hula hoop competition. you win 3 out of every 7 trials. your friend wins 5 more trials than you. how many trials are in the competition?

12 or 13. See below Use 12 first then 13

Step-by-step explanation:

Write the proportion

3:7 = x:(x + 5)         Write the proportion in fractional form.

3/7 = x / (x + 5)       Cross multiply

3*(x + 5) = 7x          Remove the brackets

3x + 15 = 7x            Subtract three x from both sides.

3x - 3x + 15 = 7x - 3x  Collect like terms

15 = 4x                      Divide both sides by 4

15/4 = 4x/4               Divide    

3.75 = x                   The question is when to round and how.

The total number of competitions was x + x + 5 = 2x + 5

total = 2*3.75 + 5

total = 7.5 + 5

Total = 12.5 which I would round to 12. If that does not work, use 13.  You round at the end.          

step-by-step explanation: