Answer:
Step-by-step explanation:
a) Let t represent the clock time (hours after midnight). The distance from home will be ...
 distance = speed × time
 jonah = 40(t -7)
 jesse = 50(t -10)
 jonah = jesse . . . . . . . same distance from home at the same time
(Note: you could let y = distance traveled and use y in both equations. That would give 2 equations in 2 unknowns, instead of 3 equations in 3 unknowns.)
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b) substituting the first two equations into the second, we get ...
 40(t -7) = 50(t -10)
 4t -28 = 5t -50 . . . . . . . divide by 10, eliminate parentheses
 22 = t
Jonah and Jesse will be at the same place at 10 p.m.
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c) We can find the distance by substituting into either equation.
 jonah = 40(22 -7) = 40(15) = 600
They will be 600 miles from home at that time.