Question 286389
D=RT
140=(20+C)T DOWN STREEM TRIP.
T=140/(20+C)
92=(20-C)T UP STREEM TRIP.
T=92/(20-C)
SET THESE 2 EQUATIONS EQUAL.
140/(20+C)=92/(20-C)
140(20-C)=92(20+C) CROSS MULTIPLY
140(20-C)=92(20+C)
2,800-140C=1,840+92C
-140C-92C=1,840-2,800
-232C=-960
C=-960/-232
C=4.138 SPEED OF THE CURRENT.
PROOF:
140/(20+4.138)=92/(20-4.138)
140/24.138=92/15.862
5.8=5.8