Question

Bhavik bought 3 liters of milk and 5 loaves of bread for a total of $11. A month later, he bought 4 liters of milk and 4 loaves of bread at the same prices, for a total of $10.

How much does a liter of milk cost and how much does a loaf of bread cost?

Answer 1

liter of milk : $ 0.75

loaf of bread : $ 1.75

Explanation:

Khan academy says so

Answer 2

the cost of a liter of milk is
`\$0.75`

the cost of a loaf of bread is
`\$1.75`

Explanation:

Let

x------> the cost of a liter of milk

y------> the cost of a loaf of bread

we know that

`3x+5y=11` ------> equation A

`4x+4y=10` ------> equation B

Multiply equation A by
`-4`

`-12x-20y=-44` -------> equation C

Multiply equation B by
`3`

`12x+12y=30` ------> equation D

Adds equation C and equation D

`-12x-20y=-44\\12x+12y=30\\ ----------\\ -20y+12y=-44+30\\ -8y=-14\\y=\$1.75`

Find the value of x

substitute the value of y in the equation A

`3x+5(1.75)=11`

`3x=2.25`

`x=\$0.75`