It takes Bill 8 hours to paint a house. It take Paul 4 hours to paint a house. And it takes Quincy 9 hours to paint a house. How many hours would it take them working together?

  2 2/35 hours

Step-by-step explanation:

In 1 hour, the total amount of the house that is painted is ...

  1/8 + 1/4 + 1/9 = 35/72 . . . of a house

We need to multiply the time (1 hour) by 72/35 to find the number of hours required for one entire house:

  72/35(1 h) = 2 2/35 h

It would take them 2 2/35 hours to paint the house working together.

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step-by-step explanation:

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".