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Working together, two ants named Aran and Beatrice can build an ant hill in 10 hours. Aran and Charlie can build the ant hill in 12 hours. Beatrice and Charlie can build the ant hill in 15 hours. How long, in hours, will it take to build the ant hill if Aran, Beatrice, and Charlie work together?

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Here we have a problem of rates of work, we want to know how long will take the 3 ants to build an ant hill if they work together.

We will find that working together, they need to work for 8 hours.

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Let's start by defining the variables that we will use:

  • A = rate at which Aran works
  • B = rate at which Beatrice works.
  • C = rate at which Charlie works.

Now let's see the given information:

"Aran and Beatrice can build an ant hill in 10 hours"

This can be written as:

(A + B)*10 h = 1 ant hill

"Aran and Charlie can build the ant hill in 12 hours"

This can be written as:

(A + C)*12 h = 1 ant hill

"Beatrice and Charlie can build the ant hill in 15 hours"

This can be written as:

(B + C)*15 h = 1 ant hill.

Then we have 3 equations:

[tex](A + B)*10 h = 1[/tex]

[tex](A + C)*12 h = 1[/tex]

[tex](B + C)*15 h = 1[/tex]

Where for commodity, I removed the "ant hill" unit.

Now we need to solve this system of equations, to do it, we need to isolate one variable in one of the equations and then replace it on another equation.

I will isolate A in the first equation:

[tex]A = \frac{1}{10h} - B[/tex]

Now we can replace it in the second equation to get:

[tex](\frac{1}{10h} - B + C)*12h = 1[/tex]

Now we can isolate C in the last equation to get:

[tex]C = \frac{1}{15h} - B[/tex]

Replacing that in the above equation we get:

[tex](\frac{1}{10h} - B + \frac{1}{15h} - B)*12h = 1\\\\\frac{1}{6h} - \frac{1}{12h}= 2*B\\\\\frac{1}{2}*\frac{1}{12h} = \frac{1}{24h} = B[/tex]

This means that Beatrice alone would construct the hill in 24 hours.

Now that we know the value of B, we can use:

[tex]C = \frac{1}{15h} - B = \frac{1}{15h} - \frac{1}{24h} = \frac{1}{40h}[/tex]

This means that Charlie needs 40 hours to finish the hill alone.

Finally, we can use [tex]A = \frac{1}{10h} - B[/tex] to find the value of A:

[tex]A = \frac{1}{10h} - B = \frac{1}{10h} - \frac{1}{24h} = \frac{7}{120h}[/tex]

Now if the 3 ants work together, the total rate at which they work is:

[tex](A + B + C) = (\frac{7}{120h} + \frac{1}{40h} + \frac{1}{24h} ) = 0.125 h^{-1}[/tex]

This means that they need to work for the inverse of that rate

[tex]\frac{1}{0.125h^{-1}} = 8h[/tex]

Working together, they need to work for 8 hours to complete an ant hill

If you want to learn more, you can read:

https://brainly.com/question/12895249

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