Hi! So, the one that doesn't belong is a) y = 4x.
I think that this doesn't belong because every other option has a number after the variable (I forget the exact term for it but it's like +7, +4, and -1 for the rest of the options)
Please let me know how I can further help you :)
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Let V, be the rate in still water and let C = rate river current
If the boat is going :
upstream, its rate is V-C and if going
downstream, its rate is V+C,
But V = 5C, then
Upstream Rate: 5C - C = 4 C
Downstream rate: 5C+C = 6C
Time = distance/Rate, (or time = distance/speed) , then:
Upstream time 12/4C and
Downstream time: 12/.6C
Upstream time +downstream time:= 2h30 ' then:
12/4C + 12/.6C = 2.5 hours
3/C + 2/C = 5/2 (2.5 h = 5/2)
Reduce to same denominator :
5C = 10 and Rate of the current = 2 mi/h
1) 135 2) 119.40 if you still need the rest reply back to this answer
