M = Tim's dollar amount
R = Rebecca's dollar amount
MR = Tim and Rebecca's dollars together
R = (M x 1/10) - 6
MR = M + ((M x 1/10) - 6)
MR = 70 + ((70 x 1/10) - 6)
MR = 70 + (7 - 6)
MR = 70 + 1
MR = 71
The last option, #4, because the least amount is -3, including -3 itself and the highest one is infinity so everything greater than -3
