Question

One who and one what cost 12 dollars. One who and one where cost 11 dollars. One what and one where cost ten dollars. How many dollars do 2 who’s cost?

Answer 1

who=x
what=y
where=a
x+y=12
x+a=11
y+a=10
add the first 2 together so it is 2 who's and a what and a where
subtract the last equation so it only leaves 2 who's
:)