4x + 6y = 230 --> [1]
1x + 1y = 40 --> [2]

Multiply [2] by 4, to get an equal coefficient of x:

4x + 6y = 230
4x + 4y = 160

Subtract:

2y = 70 --> y = 35

Substitute into [1]:

4x + 6(35) = 230 --> 4x + 210 = 230 --> 4x = 230 -210 = 20 --> x = 5

I still remember it, despite it being last millennium that I did A-Level Maths!