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Basic Math/Algebra II

Question
25. During the first 20 miles of a 50 mile bicycle race,Roger's average speed was 16mi/h. what must his average speed be during the remainder of the race if he is to finish the race in less than 2.5 hours? Greater than:

A) 24mi/h
B)8mi/h
C)12mi/h
D) 4mi/h

distance = time x speed.  So, during the first 20 miles, he averaged 16mph, so fill those values into your equation and solve for time.  20=16t or time = 20/16 = 5/4 = 1 1/4 = 1 hr, 15 mins.  So, now the rider has to do 30 miles in less than 1hr, 15mins (5/4).  So again, fill those values into your equation 30=5/4s.  Multiplying both sides of the equation by 4/5 gives you
30(4/5)=5/4(4/5)s = s = 120/5 = 24.  So, Roger needs to average greater than 24 to finish in 2.5 hrs.

Basic Math

Volunteer

Lynn Houston

Expertise

I can answer questions in basic algebra and any grade school math.

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Love math, currently helping my nephew get through Intermediate Algebra.

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I majored in Math Ed in college (but decided not to teach), so have over 40 credits of math.