Question

Solve (x of 4% solution) + (y of 12% solution) = 200 mg of 7% solution?

Answer 1

`x=125` and `y=75`.

Explanation:

We have two equations here

One - `x*4%+y*12%=200*7%`

This equation says that `x` `mg.` of `4%` and `y` `mg.` of `12%` makes `200` `mg` of `7%`.

or `x*4/100+y*12/100=200*7/100`

or `x/25+(3y)/25=14`

or `x+3y=350` ......................(A)

Two - `x+y=200` ......................(B)

Subtracting (B) from (A), we get

`2y=150` i.e. `y=75`

Hence `x=125` and `y=75`.