I'm going to do this problem with mathematical equations (I chose x to represent the first, y as the second, and z as the third)
so according to the first sentence, x+y+z=270
the second sentence is saying x+y=z+98
and the third sentence says z-47=x
I would first plug x in to my middle equation
(z-47)+y=z+98
then add 47 to both sides to get z+y=z+145
In this case we are lucky because as we go to subtract z they cancel out and we get y=145
Now plug y and x (in terms of z) into the first equation
(z-47)+145+z=270
subtract 47 from 145 to get 98
subtract that from 270 to give you z+z=172
simplify 2z=172
divide by 2 to get z=86
Now go back and plug in z to the bottom equation,
86-47=x so x is equal to 39
Overall we got x=39, y=145 and z=86
To make sure these answers are correct we want to plug the back into our original equations.
39+145+86=270 True!
39+145=184=86+98 True!
and finally 86-47=39 True!
So we know that these numbers are correct
*Just so you know it doesn't really matter which equation you plug in you substituted values into, or which one you solve for first, it's all just a matter of preference....