colin drives 10 km/h faster than fred. after 2 hours they are 200 km apart. how fast is each man driving?
two men leave the same place at the same time and drive in opposite directions. the first man drives 10 km/h faster than the second man. after 2 hours they are 200 km apart. how fast is each man driving?
Colin (c) = speed of Colin in km/h
Fred (f) = speed of Fred in km/h
c = f + 10 ← call this eq1
[c + f ] 2 = 200 ← call this eq2
substitute eq1 to eq2
[(f + 10) + f] 2 = 200
[2f + 10]2 = 200
4f + 20 = 200
divide by 4 to both side of the equation
f + 5 = 20
Fred Speed (f) = 15 km/h
substitute f to eq1
c = f + 10 ← call this eq1
c = 15 + 10
Colin speed (c) = 25 km/h