Question

Leila is participating in a 4-day cross-country biking challenge. She biked for 64, 55, and 70 miles on the first three days. How many miles does she need to bike on the last day so that her average (mean) is 60 miles per day?

a) 60 miles
b) 65 miles
c) 70 miles
d) 75 miles

Answer 1

Leila needs to bike 51 miles on the last day so that her average is 60 miles per day, which is not listed among the given answer options.

Step-by-step explanation:

Leila is participating in a 4-day cross-country biking challenge. She biked for 64, 55, and 70 miles on the first three days. To find out how many miles she needs to bike on the last day so that her average (mean) is 60 miles per day, we need to perform some calculations.

First, we calculate the total number of miles she wants to have after four days:

• 60 miles/day × 4 days = 240 miles in total

Next, we add up the miles she has biked over the first three days:

• 64 + 55 + 70 = 189 miles

Then, we subtract the total miles biked so far from the desired total to find out the miles she needs to bike on the last day:

• 240 miles - 189 miles = 51 miles

Therefore, none of the options given (a) 60 miles, (b) 65 miles, (c) 70 miles, (d) 75 miles directly matches the correct answer. Instead, the answer is 51 miles.