Not sure when i’m going to use this, but i need

To find how much older Leo is than John, we need to first assign our variables. In this case, let's say that x = Leo, y = Karla, and z = John. Now, let us turn words into numbers.
x = 2y
z = y - 7 
Next, we need to create an equation for their combined ages. This is what the equation should look like:
x + y + z = 37
Now, just substitute the expressions we found for x and z. This is what we get:
2y + y + (y - 7) = 37
Solve for y:
2y + y + y - 7 = 37
4y - 7 = 37
4y = 44
y = 11
So now we have the value for y, which is Kayla's age. Therefore, just substitute the value for y back into the equations for x and z.
x = 2(y) => x = 2(11) => x = 22
z = y - 7 => z = 11 - 7 => z = 4
Now that we have the values for x, y, and z, all we need to do now is reassign them back to their respective names. Our final answer will be: John is 18 years older than Leo. The answer to your query would be E) 18. Hope this helps and have a nice day!