1 + 1x
"the sum of one and" 1 +
"the product of" x
"one" 1 x
"and a number x" 1 x (x)
1 + 1x
He can only pick 7 different groups because 2 times 7 is 14, and there are 15 people in all.
Hope this helps. c:
Part A: c for cost. c=0.31m+0.5
0.31m is the cost per minute. 0.5 is cost per call.
Part B: 0.31m+0.5=5.15 to solve we must rearrange.
subtract 0.5 from each side giving us 0.31m=4.85
divide by 0.31 giving us m=15.65
