The answer is 4/15, because we have to get the denominaters to be the same, so the LCM of 5 and 15 is 15, so 15/5 is 3 and 4*3 is 12. Now, its 12/15-8/15 which is 4/15. Hope this helps!
Perimeter of rectangle is 2L + 2W
perimeter is 296
length of field is 79
Solve
2L + 2W = 296
2(79) + 2W = 296
158 + 2W = 296
2W = 296 - 158 = 138
W = 138/2 = 69 yards