Question

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

Answer 1

7 mice and 7 birds

Explanation:

14 heads would mean there are 14 animals in total, as each animal has one head.

Birds have two legs, and mice have four.

2+4=6

40/6=6.67 (recurring)

6.67*2=13.3 (recurring)

6.67*4=26.67 (recurring)

Animal legs can't be in decimal numbers, so we can round the numbers.

13.3 becomes 13, 26.67 becomes 27.

13+27=40

Now we can see that there are 13 bird legs and 27 mice legs.

Divide the bird legs by 2 to get 6.5

Divide the mice legs by 4 to get 6.75

Again, we can't have a decimal of an animal, so we can round.

6.5 becomes 7, and 6.75 also becomes 7.

Therefore, there is 7 of each type of animal.

Answer 2

Birds = 8

Mice = 6

Explanation:

Conditions

Let the birds = x

Let the mice = y

Equations

x + y = 14

2x + 4y = 40

Solution

Using the top equation solve for x

x = 14 - y

Use this result to substitue for x

2(14 - y) + 4y = 40

Remove the brackets

28 - 2y + 4y = 40

Combine

28 + 2y = 40

Subtract 28 from both sides

28 - 28 + 2y = 40 - 28

2y = 12

Divide by 2 on both sides

2y/2 = 12/2

y = 6

Solve for x

x + y = 14

x + 6 = 14

Subtract 6 from both sides

x + 6 - 6 = 14 - 6

x = 8