Question

Kyle asks his friend Jane to guess his age and his grandmother’s age. Kyle says his grandmother is not more than 80 years old. He says his grandmother’s age is, at most, 3 years less than 3 times his own age. Jane writes this system of inequalities to represent k, Kyle’s age, and g, Kyle’s grandmother’s age. Inequality 1: g > 80 Inequality 2: g ≤ 3k – 3 Which inequality did Jane write incorrectly, and how could it be corrected?

Answer 1

It's 'Inequality 1 is incorrect; it should be g ≤ 80' on edge

Answer 2

#1 is incorrect. The first equation says that his grandmother is not more than 80 years old. If you confine yourself to whole numbers, then she could be 80 but not more. That inequality should be written as g < 81 or if you are a purist, g≤ 80.

The second equation is correct. At the very most her age is equal to 3k - 3 so at most it would be written as g = 3k - 3.

Since it is not that much, you would write it as g ≤ 3k - 3