Question #ce8dd

1 Answer
Nov 27, 2017

In #4 " hours"#

Explanation:

Since they are travelling in opposite directions, the distance between them is increasing at the rate of
#55 " mph" + 45" mph"=100" mph"#

They will be #400 " miles"# apart in
#color(white)("XXX")(400 " miles")/(100 " miles per hour")=4" hours"#