7th grade math question?
can sombody help me out here or tell me how to go about doing this please??here is the question:A college has ten instructors qualified to teach a special computer lab course which requires two instructors to be present. How many different pairs of teachers could there be?
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9+8+7+6+5+4+3+2+1=45 pairs
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An alternative solution:
C(10,2) = 10*9/2 = 45.
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This is a statistics problem, specifically a combination. The formula for a combination is:
C (n, r) = n!/((n-r)!r!)
Where n is the number of possible choices and r is the size of each combination. In this case, n=10, r=2.
C(10,2) = 10!/((10-2)!2!)
or
C(10,2) = 10!/(8!2!) = 3,628,800/(40,320*2)
C(10,2) = 45
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