Question

Dan is training for a bike race. He wants to bike 300 miles over the next couples of weeks. Dan biked 29 miles a day for 3 days. Then, he biked 32 miles a day for 4 days. How many more miles does he still have to bike to get to his goal of 300 miles?

A. Sara estimated that Dan would need to bike about 80 more miles to get to his goal of 300 miles. Is this a reasonable estimate? Why or why not?

B. Write an equation for this problem with a letter standing for the unknown quantity.

C. Solve the problem. Show your work.

Answer 1

Explanation:

a. Sara's estimate is reasonable because:

Dan has biked for 7 days so far, 29 miles for 3 days and 32 miles for 4 days.

If you round 29 and 32 up and down respectively to 30, then Dan will of have ridden about 30 * 7, or 120 miles so far. 300-120 is 80, so that is a good estimate.

b. If x stands for the miles Dan still needs to bike, then:

(29*3) + (32*4) + x = 300

c. 87 + 128 + x = 300

x = 85