Here it is again.
To figure out the solution, you have to think about how much each item represents.
The lipsticks equal 30 divided by three, so each tube of lipstick is equal to 10.
Lipstick (10) plus mirror plus mirror equals 20, so a mirror equals five.
Mirror (5) plus two nail polishes plus two nail polishes equals nine, which means that a nail polish equals two.
Therefore, one nail polish equals one.