Question 416345
Ruth jogs while Jerry rollerblades. Jerry rollerblades 2.9 miles per hour faster than Ruth jogs.
 When Jerry has rollerbladed 5.7 miles, Ruth has jogged 3.4 miles.
 Find Ruth's jogging speed.
:
Let s = R's jogging speed
then
(s+2.9) = J's rolling speed
:
Write a time equation; time = dist/speed
:
rolling time = jogging time
{{{5.7/(s+2.9)}}} = {{{3.4/s}}}
Cross multiply
5.7s = 3.4(s+2.9)
5.7s = 3.4s + 9.86
5.7s - 3.4s = 9.86
2.3s = 9.86
s = {{{9.86/2.3}}}
s = 4.287 mph is R's jogging time 
:
:
Check solution by finding the times (J's speed 2.9+4.287 = 7.187)
5.7/7.187 = .793 hrs
3.4/4.287 = .793 hrs; confirms our solution of s = 4.287