Evaluate the following expression. 3^-2
1 answer:
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Answer:
40/9
Step-by-step explanation:
Use the work formula, +
=
, where A is the amount of time it takes one person, B is the amount of time it takes another person, and T is the time it takes for them to work together.
Plug in the times for David and Alex alone:
+
=
Find the least common denominator, which is 40.
+
=
=
Cross multiply and solve for T:
9T = 40
T = 40/9
So, if they worked together, it would take them 40/9 hours