Michael breeds chickens and ducks. Last month, he sold 50 chickens and 30 ducks for $550. This month, he sold 44 chickens and 36 ducks for $532. How much does a chicken cost, and how much does a duck cost?
Answers
★ Given :
Cost of 50 chickens and 30 ducks = $ 550
Cost of 44 chickens and 36 ducks = $ 532
★ To find :
Cost of chicken and duck
★ Solution :
Assume :
Cost of chicken = x
Cost of duck = y
According to question :
50x + 30y = 550 ......(1)
44x + 36y = 532......(2)
(1) - (2)
(50x + 30y) - (44x + 36y) = 550 - 532
50x + 30y - 44x - 36y = 18
6x - 6y = 18
6(x - y) = 18
x - y = 18/6
→ x - y = 3 ....(3)
In equation 1 ,
50 x + 30y = 550
taking 10 common
10(5x + 3y) = 550
5x + 3y = 550/10
5x + 3y = 55
by taking 3 common
3(5/3 x + y) = 55
by dividing 3 on both sides
5/3x + y = 55/3 .....(4)
(3) + (4)
x - y + 5/3 x + y = 3 + 55/3
x + 5/3 x = 64/3
8/3 x = 64/3
by multiplying 3 on both sides
8x = 64
x = 64/8
→ x = 8
→ Cost of chicken = $ 8 ..
by putting value of x in equation 3
x - y = 3
8 - y = 3
y = 8 - 3
→ y = 5
→ Cost of ducks = $5..
Answer: –
$8 a chicken, $5 a duck
Explanation: –
c=chickens
d=ducks
2 equations, 2 unknowns c and d
50c+30d=550 and 44c+36d=532
Solve for d:
50c+30d=550
→30d=550-50c
→d=(550-50c)/30
Plug d into 2nd equation:
44c+36((550-50c)/30)=532
→44c+6/5 (550-50c)=532
→44c+6(110-10c)=532
→44c+660-60c=532
→660-532=60c-44
→128=16c
→c=128/16=8
★$8 per chicken★
Plug c=8 back in equation 1:
50(8)+30d=400+30d=550
→30d=550-400=150
→d=150/30=5
★ $5 per duck★