Question

If x + y equals to 10 and x - 2 y equals 8 what is the value of 3 y

Answer 1

We have this first condition given:

`x+y=\text{ 10 (1)}`

And the second one:

`x-2y=\text{ 8 (2)}`

If we solve for x from equation (1) we got:

`x=\text{ 10}-y\text{ (3)}`

And if we solve for x from equation (2) we got:

`x=\text{ 8+2y (4)}`

Now we can set equal equations (3) and (4)

`10-y=\text{ 8+2y}`

And solving for y we got:

`18=\text{ 3y }\rightarrow\text{ y= }(18)/(3)=\text{ 6}`

Final answer:

`y=\text{ 3}\cdot6\text{ = 18}`