The given inequality is expressed as
50 - 8t < 90
The first step is to subtract 50 from both sides. We have
50 - 50 - 8t < 90 - 50
- 8t < 40
The next step is to divide by - 8. Since we are dividing by a negative number, the inequality would be reversed. It changes from < to >. Thus, we have
- 8t/- 8 > 40/- 8
t > - 5
The arrow on the number line was supposed to point to the right side of - 5. Thus,
Mary divided both sides of the inequality by a negative value, so she needed to reverse the same inequality symbol
