SOLUTION: The work principal states that if on person can do a job in time ‘a’ and another can do the same job in time ‘b’ that they can do the job together in time ‘t’. This is demonstrated

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Question 84664: The work principal states that if on person can do a job in time ‘a’ and another can do the same job in time ‘b’ that they can do the job together in time ‘t’. This is demonstrated by the equation:
1 + 1 = 1
a b t
Write the expression in terms of a:
And then use t = 5 hours and b = 8 hours, approximately what is a?

Answer by funmath(2933) About Me  (Show Source):
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The work principal states that if on person can do a job in time ‘a’ and another can do the same job in time ‘b’ that they can do the job together in time ‘t’. This is demonstrated by the equation:
1 + 1 = 1
a b t
Write the expression in terms of a:
1%2Fa%2B1%2Fb=1%2Ft
LCD=abt Multiply each term by the LCD and clear your fractions.
abt%281%2Fa%29%2Babt%281%2Fb%29=abt%281%2Ft%29
bt%2Bat=ab solve for a
bt%2Bat-at=ab-at
bt=ab-at
bt=a%28b-t%29
bt%2F%28b-t%29=a%28b-t%29%2F%28b-t%29
bt%2F%28b-t%29=a
a=bt%2F%28b-t%29
And then use t = 5 hours and b = 8 hours, approximately what is a?
a=%288%29%285%29%2F%28%288%29-%285%29%29
a=40%2F3
a=13 1/3 hrs or 13.333 hrs or 13 hrs (1/3)(60)min=13hr and 20 min
I don't know what form of an aswer that your teacher prefers, they're all valid answers.
Happy Calculating!!!