Question

Question #03002

Answer 1

Use a simultaneous equation.
Barako coffee…`7.2`kg Arabica coffee…`4.8` kg

Explanation:

Let `x` the mass of the Barako coffee and `y` the mass of the Arabica coffee. (Unit in kg).

Total 12 kilograms of coffee beans are used.
`x+y=12` ・・・[1]

Total cost is `360*12=4320` pesos.
`320x+420y=4320`・・・[2]

To solve [1] and [2], multiple both sides of [1] by `320`.
`320x+320y=3840`・・・[3]

`" "` [2] `320x+420y=4320`
`" -)"` [3]`320x+320y=3840`
`" "100y=480`
Therefore,
`y=480/100=4.8`
and
`x=12-4.8=7.2`

So, `7.2` kilograms of Barako coffee and `4.8` kilograms of Arabica coffee are used.