Question

1. you want to run an average of at least 22 miles each week for four weeks to prepare for a marathon. during the first 3 weeks of training, you run 20 miles, 22 miles, and 21 miles. how many miles must you run in the fourth week to meet your goal?

Explanation:

Step1: Define total miles needed

To average at least 22 miles over 4 weeks, total miles needed: \( 22\times4 = 88 \)

Step2: Calculate miles run in first 3 weeks

First 3 weeks: \( 20 + 22 + 21 = 63 \)

Step3: Find miles needed in 4th week

Let \( x \) be miles in 4th week. \( 63 + x \geq 88 \) → \( x \geq 88 - 63 = 25 \)

Answer:

You must run at least 25 miles in the fourth week.