<PRE><B>Question 444770</B>
40/x=15/x-20
40x-800=15x
25x=800
x=32
Carlos goes 32 mph. Paul goes 12 mph..
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392/x=322/x-20
392x-7840=322x
70x=7840
x=112
The passenger train runs 112 mph.  The freight train runs 92 mph..
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1/8+1/4=1/t
3/8=1/t
3t=8
t=8/3
Shelley and Karen can finish a fence in 8/3rds hours working together..</PRE>