Question 569730
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
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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.