first u multiply 30 by all those numbers
30 x 37= 1110
30 x 88= 2640
So in conclusion she needs to make 88 sales to reach her goal.
In first place you Know that Sheila's salary is $ 1100 and $30 for every sale, as she want to earn $2630 this month you must substrac 1100 of 2630
then $ 2630-1100 = $1530 now you establish a proportion of quantities
1 sale_____ $30
x sale____ $1530
X = 1*$1530/$30 = 51, SHE NEED TO MAKE 51 SALES TO OBTAIN $ 2630