If we are eliminating x, we would multiply the 2nd equation by -5
5x + 18y = 23
x + 3y = 2....multiply by -5
-----------------
5x + 18y = 23
-5x - 15y = - 10 (result of multiplying by -5)
----------------add
0 + 3y = 13.....bye-bye x :)
ITS C - Factor 6 out of the variable terms
There could be 35 toffees in the box.