How many kilograms of butter of rs 140 per kg must be mixed with 20 kg of butter worth rs 150 per kg to produce a mixture worth rs 144 per kg. explain this

Let x kg of butter @Rs140/kg be added to 20kg of butter @Rs 150/kg

total price = 140×x + 150×20 = 140x + 3000

after mixing, (x+20) kg of butter is produced @Rs144/kg 

144×(x+20) = 140x+3000

⇒144x + 144×20 = 140x + 3000

⇒ 144x - 140x = 3000 - 144×20

⇒ 4x = 3000-2880 = 120

⇒ x = 120/4 = 30kg

So required answer is 30

the correct functions are

h(x) = 3x + 2  

g(x) = 2^x

step-by-step explanation:

i proceed to calculate the different values ​​of k (x)

case 1)  k(x) = g(x) ∘ h(x)

g(x) ∘ h(x)=g(h(x))

k(x) = [2]^[3x + > is the option  4. k(x) = 2^(3x + 2 )

case 2)  k(x) = g(x) + h(x)

k(x) = [2^x]+[3x + 2]=2^x+3x+> is the option  1.) k(x) = 2^x + 3x + 2

case 3)k(x) = h(x) ÷ g(x)

k(x) =  [3x + 2]/[2^x]=3x/(2^x)+2/(2^x)=3x*(2^-x)+2^(1-x)

is the option  3.)   k(x) = (3x)2^(-x) + 2^(-x + 1 )

case 4)k(x) = g(x) - h(x)

k(x) =  [2^x]-[3x + 2]=2^x-3x-> is the option  2.) k(x) = 2^x - 3x - 2 

case 5)  k(x) = g(x) × h(x)

k(x) = [2^x]*[3x + > is the option  5.) k(x) = 2^x(3x + 2)

case 6)k(x) = h(x) ∘ g(x)

h(x) ∘ g(x)=h(g(x))

k(x)=3*[2^x]+> is the option  6. k(x) = 3(2^x) +2