Question 775118
let first number be x and second one y
x+y=42
3x=4y
solve the system of equations
x=42-y
3(42-y)=4y
126-3y=4y add 3y to each side
126=7y divide each side by 7
18=y
so if y is 18 then x=42-y so x=42-18=24