Susan saw birds and mice eating seeds on the ground. She counted 14 heads and 40 legs in total. How many birds and mice are on the ground?

Respuesta :

Answer:

8 birds and 6 mice

Step-by-step explanation:

Given:

Number of heads = 14

Number of legs = 40

Required

How many birds and mice are on the ground?

Let M represents Mice and B represents Birds

Birds and Mice have 1 head each;

So;

[tex]B + M = 14[/tex]

Birds have 2 legs; Mice have 4 legs

So;

[tex]2B + 4M = 40[/tex]

At this point, we have two equations;

Make B the subject of formula in the first equation

[tex]B + M = 14[/tex] becomes

[tex]B = 14 - M[/tex]

Substitute 14 - M for B in the second equation

[tex]2(14 - M) + 4M = 40[/tex]

Open bracket

[tex]28 - 2M + 4M = 40[/tex]

[tex]28 + 2M = 40[/tex]

Subtract 28 from both sides

[tex]28 - 28 + 2M = 40 - 28[/tex]

[tex]2M = 40 - 28[/tex]

[tex]2M = 12[/tex]

Divide both sides by 2

[tex]\frac{2M}{2} = \frac{12}{2}[/tex]

[tex]M = 6[/tex]

Recall that [tex]B = 14 - M[/tex]

So;

[tex]B = 14 - 6[/tex]

[tex]B = 8[/tex]

Hence, there are 8 birds and 6 mice