Question

BRAINLIESTTT ASAP! PLEASE HELP ME :)

Answer 1

Answer:  18/5 hours, or 3.6 hours

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Work Shown:

x = amount of time it takes Blake to do the job by himself

y = amount of time it takes Ned to do the job by himself

z = time it takes if they worked together

In this case,

x = 9 and y = 6

Use those values to find z.

$\frac{1}{x}+\frac{1}{y} = \frac{1}{z}\\\\\frac{1}{9}+\frac{1}{6} = \frac{1}{z}\\\\\frac{2}{18}+\frac{3}{18} = \frac{1}{z}\\\\\frac{2+3}{18} = \frac{1}{z}\\\\\frac{5}{18} = \frac{1}{z}\\\\5z = 18\\\\z = \frac{18}{5}\\\\z = 3.6$