M and B leave their campsite and walk in opposite directions around a lake. If the shoreline is 15 miles long, M walks 0.5 miles per hour faster than B and they meet in 2 hours...how fast does each walk?

1 Answer
Jun 23, 2016

M walks at 4mph, B walks at 3.5mph

Explanation:

Sx denotes speed of person x

SM=SB+0.5 as M is walking 0.5 mph faster than B

D=SMt t being the amount of times passed (in hours)

D=15(SBt) we know since M is walking faster B must meet at some location minus from the max location (as continues walking round)

15(SBt)=SMt since D = D

t=2 as 2 hours - substitute in

15SB(2)=SM(2)

SM=SB+0.5 so (as travelling faster) - substitute in

152SB=2(SB+0.5) expand and simplify

SB=3.5 Speed of B = 3.5mph

SM=SB+0.5
SM=3.5+0.5=4 Speed of M = 4mph