Question

A farmer looks into the barnyard at his pigs and chickens and he counts 169 heads and 398 feet how many pigs and chickens are their?

I need an equation PLEASE

Answer 1

@PJohnson89 how many legs a chicken has? and a pig?

Answer 2

X = Pigs
Y = Chickens

Total heads (assume 1 per pig and 1 per chicken) = 169
Total legs (assume 4 per pig and 2 per chicken) = 398

X + Y = 169 heads

4X + 2Y = 398 legs

You now have two equations with two unknowns, ready to solve.

Y = 169 - X

Substitute for Y

4X + 2(169 - X) = 398

4X + 338 - 2X = 398

2X = 60

X = 30 Pigs

now if you still didn't understand .. raise questions ;)

Answer 3

@PJohnson89 should i be more clear ?

Answer 4

yes

Answer 5

okay .. let x = pigs and y = chickens
got it ?

Answer 6

y

Answer 7

in maths we use variables such as x and y , so that doin eqns will be easy or say we can even take for chickens = C and pigs = P if that is what you prefer :)

Answer 8

ok

Answer 9

okay .. now chickens = C and pigs = P

Answer 10

given that p + c = 169 (head)
and 4p+2c = 398 (legs)

because head is one for both pig and chicken and leg for a chicken is two and for a pig 4 .. got it ?

Answer 11

yes

Answer 12

okay .. good

now ,
Multiply 1st equation by 2

2 P + 2 C = 338
4 P + 2 C = 398 ( CHANGING SIGNS IN THE 2ND EQN)

-2P - 0 = -60
2P = 60
P = 30



SO MUCH UNDERSTOOD ?

Answer 13

@PJohnson89 dealing with a problem ?

Answer 14

why does the sign change in the second half

Answer 15

it is like that .. that is a part of math .. like let me ask you what is 2 * 3 ?

Answer 16

6

Answer 17

yes .. just like that in quadratic eqns sign changes in the second eqn which is universally acceptd .. got it ?

Answer 18

ok

Answer 19

can you proceed now ? we have found that pig = 30 now you try doing for chickens ;)

Answer 20

ok thank you

Answer 21

do for chicken .. or you want me to do that too ?

Answer 22

I will try it tomorrow I have to go to work in the morning

Answer 23

hm..