Answer:
15
Step-by-step explanation:
Let x represent the number of algebra problems. Then the number of geometry problems was 27-x and the total working time was ...
2x +5(27 -x) = 90
-3x = 90 -135 . . . . subtract 135
x = -45/-3 = 15 . . . divide by -3
Rob had 15 algebra problems for homework.
So to get the answer you do 100100100+303030-101010 which = 100302120 x 10 (the amount she/he gets for each subscriber) which is the amount of money Kiersten earned.
Hope this helped