19.
`{(6 * s + 6 * u = 46.50, -),
(4 * s + 6 * u = 37.50, ):}`
`"  "bar(2 * s \ color(white)(+ 0 * u) = color(white)(0)9.00)`

`2 * s = 9`
`s = 9 // 2 = 4.50`

`4 * s + 6 * u = 37.50`
`4 * 4.50 + 6 * u = 37.50`
`6 * u = 37.50 - 18.00`
`u = 19.50 // 6 = 3.25`

`1 * s + 2 * u = 1 * 4.50 + 2 * 3.25 = 4.50 + 6.50 = color(red)11.00`

Ellenőrzés:
`6 * s + 6 * u = 6 * 4.50 + 6 * 3.25 = 27 + 19.50 = 46.50`
`4 * s + 6 * u = 4 * 4.50 + 6 * 3.25 = 18 + 19.50 = 37.50`


20.
`(x + 3.75) // 3 = 2.73`
`x + 3.75 = 2.73 * 3`
`x = 8.19 - 3.75 = color(red)4.44`

Ellenőrzés:
`(x + 3.75) // 3 = (4.44 + 3.75) // 3 = 8.19 // 3 = 2.73`