there are 15 animals in the field. some are goats and some are ducks. there are 46 legs in all.how many of each animal are in the field

Question

this si very difficult

Answer 1

There are 15 animals in the field. some are goats and some are ducks. there are 46 legs in all.

How many of each animal are in the field?

Eqn 1 G+D=15

Eqn 2 4G + 2D = 46

 

 

Solve Eqn 1 for D

D=15-G

substitute into Eqn 2

4G+ 2(15-G) = 46

4G + 30 – 2G = 46

2G = 16

G= 8

Answer

8 Goats

7 Ducks

 

 

 

Answer 2

d = ducks

g = goats

 

d + g = 15

2d + 4g = 46

 

Lets use elimination.  Multiply 1st equation by 

-2 and add to eliminate d and solve for g

 

-2d - 2g = -30

 2d + 4g = 46

-------------------

       2g = 16

 

Finish solving for g to find number of goats.

Then use d + g = 15 to find number of ducks.