Question

felipe is participating in a 5 - day cross - country biking challenge. he biked for 56, 59, 60, and 61 miles on the first four days. how many miles does he need to bike on the last day so that his average (mean) is 57 miles per day?

Explanation:

Step1: Calculate total miles needed

The average is 57 miles per day for 5 days.
$$\text{Total miles needed}=57\times5 = 285$$

Step2: Calculate sum of first - four - day miles

Sum of first four - day miles: \(56 + 59+60 + 61\).
$$56+59+60 + 61=(56 + 61)+(59 + 60)=117+119 = 236$$

Step3: Find miles for the last day

Let \(x\) be the miles on the last day. Then \(x=\text{Total miles needed}-\text{Sum of first - four - day miles}\).
$$x=285-236=49$$

Answer:

49