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# 3 more questions on Algebra

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1)   All of the members of our spray-painting team paint at the same speed. If 5 team members can paint a certain wall in 27 minutes, then how many minutes would it take 15 of our team members to paint the same wall?

2)    All of the members of our spray-painting team paint at the same speed. If 8 team members can paint a 5000 square foot wall in 30 minutes, then how many minutes would it take the 8 members to paint an 8000 square foot wall?

3)   All of the members of our spray-painting team paint at the same speed. If 12 team members can paint a 2400 square foot wall in 45 minutes, then how many minutes would it take for 9 team members to paint a 3600 square foot wall?

Oct 26, 2017

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Here's 1

We don't need much math here.....if 5 members paint the wall in 27 minutes.....3 times as many workers - 15 -  must take 1/3 as long  = 9 minutes

Here's 2

8 workers  -  5000 sq ft   -   30 minutes

Here's the way I like to think of these.......in one minute....the 8 workers would paint

5000/ 30  =  500/3 sq ft...so....to paint 8000 sq ft would take   (8000) / (500/3)  =

8000 * 3 / 500  =    48 minutes

Here's the last one :

Using the same approach as 2...we have

12 -  2400   - 45

In 1 minute, the 12 members paint  2400/45  = 160/3 sq ft

So...1 worker can paint (1/12)  of this  = ( 160/3 ) (1/12)  = 160 / 36 sq ft

So....in 1 minute  9 workers can paint 9 times as much  =  9 * 160 / 36  =  40 sq ft

So....it will take 9 workers    3600 / 40   =  90 minutes to paint 3600 sq ft

Oct 26, 2017