frank can row 30 miles down stream in 2 hours and 12 miles u

frank can row 30 miles down stream in 2 hours and 12 miles upstream in 3 hours. what is the rate he rows in still water and the rate of the current

Solution

D=RT
30=2(R+C) OR 30=2R+2C MULTIPLY BY 3
12=3(R-C) OR 12=3R-3C MULTIPLY BY 2 & ADD.
90=6R+6C
24=6R-6C
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114=12R
R=114/12
R=9.5 IS THE RATE OF THE ROWING IN STILL WATER.
90=6(9.5+C)
90=57+6C
6C=90-57
6X=33
C=33/6
C=5.5 IS THE RATE OF THE CURRENT.
PROOF:
24=6*9.5-6*5.5)
24=57-33
24=24