77+72=149
149/2=74.5
through the process of elimination, I found that Jim needs to get an 88 or higher to receive an average of 79 or greater.
77+72+88=237
237/3=79
The equation would be 0.05x + 3.15 = 5.10
0.05x = 1.95 (subtraction)
x = 39 (division)
39 minutes
1 and 18
2 and 9
3 and 6 or of you want the set
1,2,3,6,9,18
