Rie has 3000 dollars in her savings and needs to buy an 800 dollar laptop. Rie takes out 100 dollars for food every 2 weeks. Write an inequality to explain

Question

Rie goes to San Diego State University. She has $3,000 in her savings account. She needs to buy a small laptop computer before the next semester. The laptop costs $800. Every 2 weeks she withdraws $100 from her savings account for food. How many times can Rie withdraw money for food? Write an inequality to explain.

Answer 1

If x = the number of times that Rie withdraws money from her savings account, then we can write the following inequality:

 

3000 - 100x ≥ 800

 

(This assumes that Rie is not adding any additional money to her savings account)

 

-100x ≥ -2200

 

x ≤ 22 (we must flip the inequality symbol when dividing by a negative number)

 

Rie can withdraw money from her savings account up to 22 times and still have enough money to pay for the laptop.