On the first year, two cows produced 8100 liters of milk. On the second year, their production increased by 15% and 10% respectively, and the total amount of milk increased to 9100 liters a year. How many liters of milk from each cow in each year?
Answer:
Step-by-step explanation:
Let:
x = liters of milk produced by the first cow
y = liters of milk produced by the second cow
let’s convert percentage values to decimal
10% = 0.1
15% = 0.15
Solution:
On the first year,
x + y = 8100 <=== equation 1
On the second year
(x + 0.1x) + ( y + 0.15y) = 9100
1.1x + 1.15y = 9100 <=== equation 2
Two equations and two unknowns. Solving for x and y using substitution method;
from equation 1
x + y = 8100
y = 8100 -x <=== equation 3
susbstitute equation 3 in equation 2
1.1x + 1.15y = 9100
1.1x + 1.15(8100 – x) = 9100
1.1x + 1.15(8100) – 1.15x = 9100
-0.05x + 9315 = 9100
0.05x = 215
x = 215/0.05
x = 4300 answer
y = 8100 – x = 8100 – 4300 = 3800 answer
