Question 91212
20/3=S+C S=SPEED & C=CURRENT
20/4=S-C NOW ADD THESE TWO EQUATIONS
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20/3+20/4=2S
(20*4+20*3)/12=2S
(80+60)/12=2S
140/12=2S
2S=140/12
2S=11.6667
S=11.6667/2
S=5.833 ANSWER FOR THE SPED OF THE SAIL BOAT.
20/4=5.8333-C
5=5.8333-C
C=5.8333-5
C=.8333 SPEED OF THE CURRENT.
PROOF
20/3=5.8333+.8333
6.6667=6.6667