Writing an Inequality for a Real-World Situation

There are many real-world situations, which we can reduce to inequalities and if needed, we solve them as well.

Shawna needs to buy some pencils and an eraser. She can spend no more than $9. The eraser costs $1 and the pencils cost $0.25 each. Let the number of pencils Shawna buys be p. Write an inequality for this situation.

Solution

Step 1:

Given eraser cost = $1; pencil cost = $0.25

Amount paid = 0.25p + 1 ≤ 9

Step 2:

Inequality representing the above real-world situation is 0.25p + 1 ≤ 9

More than 370 students went on a field trip. Twelve buses were filled and 10 more students traveled in a car. Let s represent the number of students in each bus. Write an inequality for this situation.

Solution

Step 1:

Number of buses = 12; Students in each bus = s; students in car = 10; Total students = 12s + 10 > 370

Step 2:

Inequality representing the above real-world situation is 12s + 10 > 370