My Math Forum  

Go Back   My Math Forum > High School Math Forum > Algebra

Algebra Pre-Algebra and Basic Algebra Math Forum

LinkBack Thread Tools Display Modes
October 29th, 2010, 08:29 PM   #1
Joined: Oct 2010

Posts: 1
Thanks: 0

Distance/Rate ??

Joe & Bill live 20 miles apart. At 9, Bill and Joe each take off on their bicycles riding toward each other, Bill at 8 miles an hour, and Joe at 7 miles an hour. At the moment Bill leaves, a fly leaves from Bill's handlebars and flies at 10 miles per hour to Joe's handlebars, then returns immediately to Bill's handlebars, and keeps going back and forth between the bikes until Joe & Bill meet.

How far did the fly fly?
mrjames is offline  
October 29th, 2010, 09:04 PM   #2
Senior Member
MarkFL's Avatar
Joined: Jul 2010
From: St. Augustine, FL., U.S.A.'s oldest city

Posts: 12,211
Thanks: 521

Math Focus: Calculus/ODEs
Re: Distance/Rate ??

The fly flies at 10 mph the entire time Bill and Joe are traveling , so we merely need to find how long it takes Bill and Joe to meet, time = t.

Let x be the distance Bill travels, and y be the distance Joe travels. This gives us:

x + y = 20

using distance = speed*time, we have

8t + 7t = 20

Combine like terms.

15t = 20

Solve for t.

t = 4/3

Let d be the distance for the fly, and use again distance = speed*time:

d = (10 mph)(4/3 hr) = 40/3 miles.
MarkFL is offline  

  My Math Forum > High School Math Forum > Algebra

distance or rate

Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Distance, rate, and time help. HellBunny Algebra 3 August 16th, 2012 12:46 PM
D=RT (Distance = Rate x Time) Mighty Mouse Jr Algebra 4 July 9th, 2010 06:47 PM
D=RT (Distance = Rate x Time) Mighty Mouse Jr Algebra 3 July 9th, 2010 03:42 PM
D=RT (Distance = Rate x Time) Mighty Mouse Jr Algebra 4 June 29th, 2010 03:24 PM
help on distance, rate, time marie789 Algebra 2 December 11th, 2007 08:13 PM

Copyright © 2019 My Math Forum. All rights reserved.