+0

help

0
86
1

Beatrice traveled the last 220 miles of the trip at 55 miles per hour. The entire trip covered 430 miles and took 7 hours. What was her rate for the first 210 mile?

Guest May 4, 2017
Sort:

1+0 Answers

#1
0

Beatrice traveled the last 220 miles of the trip at 55 miles per hour. The entire trip covered 430 miles and took 7 hours. What was her rate for the first 210 mile?

Let Beatrice's average speed for the first 210 miles = S

220/55 + 210/S

Solve for S:
4 + 210/S = 7

Bring 4 + 210/S together using the common denominator S:
(2 (2 S + 105))/S = 7

Multiply both sides by S:
2 (2 S + 105) = 7 S

Expand out terms of the left hand side:
4 S + 210 = 7 S

Subtract 7 S + 210 from both sides:
-3 S = -210

Divide both sides by -3:
Answer: |S = 70 - miles per hour, her speed for the first 210 miles.

Guest May 4, 2017
edited by Guest  May 4, 2017
edited by Guest  May 4, 2017

25 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details