EXPLANATION
Let's see the facts:
Ipad pen cost = -$105
Best friend ----> +$12
---------------
-$93
Babysitting Saves +$20/week
We are still needing $93 dollars to buy the pen, so, if she earns $20 peer week, then she should work:
$93 = 20 $/week * number of weeks
Calling x to the number of weeks and turning this into an inequality:
12 + 20x ≥ 105
Subtracting -12 to both sides:
20x ≥ 105-12
Simplifying:
20x ≥ 93
Dividing both sides by 20:
x ≥ 93/20
Simplifying:
x ≥ 4.65
Answer: Amelia should at least work 5 weeks in order to save the money to buy the Ipad pen.