Question 569730: I need help with these two word problems
In 2005, there were 66,000 new cases of skin cancer in the United States. Men
represented 10,000 more cases than women. How many new cases of skin cancer
were there for men and for women?
A boat can travel 36 miles upstream in the same time that it can travel 54 miles
downstream. If the speed of the current is 3 miles per hour, what is the speed
of the boat without a current?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! In 2005, there were 66,000 new cases of skin cancer in the United States. Men
represented 10,000 more cases than women. How many new cases of skin cancer
were there for men and for women?
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# of female cases: x
# of male cases: x + 10,000
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Equation:
x + x+10000 = 66000
2x = 56000
x = 28000 (female cases)
x+10000 = 38000 (male cases)
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A boat can travel 36 miles upstream in the same time that it can travel 54 miles downstream. If the speed of the current is 3 miles per hour, what is the speed of the boat without a current?
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Upstream DATA:
distance = 36 miles ; rate = b-3 mph ; time = 36/(b-3) hrs
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Downstream DATA:
distance = 54 miles ; rate = b+3 mph ; time = 54/(b+3) hrs
----
Equation:
time = time
36/(b-3) = 54(b+3)
2/(b-3) = 3/(b+3)
Cross-multiply:
2b+6 = 3b-9
b = 15 (speed of the boat in still water)
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Cheers,
Stan H.
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