Question

(Max Points) Do not answer if you’re not 100% sure. I’ll report if wrong.

Answer 1

Answer:

B

Step-by-step explanation:

Rocco:  of the job per hour

Giulia:  of the job per hour

Together:  of the job per hour

Rocco + Giulia = Together

$\frac{1}{7} +\frac{1}{x} =\frac{1}{3}$

$\frac{1}{7} (21x)+\frac{1}{x}(21x) =\frac{1}{3}(21x)$

3x + 21 = 7x

       21 = 4x

$x=\frac{21}{4}$

It will take Giulia$\frac{21}{4} =5\frac{1}{5}$hours to paint the room by herself.

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Giulia:$r= \frac{1}{x} =\frac{4}{21\\}$

B)$\frac{3}{7} +3(\frac{4}{21})=1$

$\frac{3}{7} +\frac{4}{7} =1$

$\frac{7}{7} =1$

1=1

so it's true

Answer 2

Answer:

• B. 3/7 + 3r = 1

Step-by-step explanation:

Job can be determines as:

• Job = time*rate

We have:

• Time 3 hours and
• Rates 1/7 and r

Sum of the parts completed by both Rocco and Giulia gives the job, which is considered as a whole or 1:

• 1 = 3(1/7 + r)
• 1 = 3/7 + 3r

or

• 3/7 + 3r = 1

Correct choice is B