Answer:
Speed of river's current = 5 mph
Step-by-step explanation:
Let 'd' be the distance covered
Let x be the speed of the rivers current
Speed upstream = 15-x
speed downstream = 15+x
Time = distance / speed
time upstream = 
time downstream = 
the ferry trip upstream takes twice as long as its return trip downstream
= 
divide both sides by d
= 
cross multiply
Add 2x on both sideds
subtract 15 from both sides and divide by 3
x=5
Speed of river's current = 5 mph
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Answer: 0.206
Step-by-step explanation: the probability of employees that needs corrective shoes are =8%= 8/100 = 0.08
Probability of employees that needs major dental work = 15% = 15/100 = 0.15
Probability of employees that needs both corrective shoes and dental work = 3% = 3/100 = 0.03
The probability that an employee will need either corrective shoes or major dental work = (Probability an employee will need correct shoes and not need dental work) or (probability that an employee will need dental work or not corrective shoes)
Probability of employee not needing corrective shoes = 1 - 0.08 = 0.92
Probability of employee not needing dental work = 1 - 0.15 = 0.85
The probability that an employee will need either corrective shoes or major dental work = (0.08×0.85) + (0.15×0.92) = 0.068 + 0.138 = 0.206 = 20.6%
The probability that an employee will need either corrective shoes or dental work = 0.206.
Please note that the word "either" implies that we must choose one of the two options (corrective shoes or dental work) and not both.
Answer:
c(x-3)-4=b(x+7)
(cx-c•3)-4=b(x+7)
cx-3c-4=b(x+7)
cx-3c-4=bx+b•7
-3c-7b-4=bx-cx
x(b-c)=-3c-7b-4
x(b-c)/b-c = -3c-7b-4/b-c
x=-3c+7b+4/b-c
