Idont get it i tried working on it and its hard

On the cube, it measures in numerical order 1 to 6, so:
1,2,3,4,5,6.
We are finding how much red fabric was used for even numbered sides.

So we are looking for sides 2,4,6

Since 20 in. is measured on a side, we can determine the area: 20*2= 40 in.^2 (all sides are same and length*width)

Now we have how much fabric is used on each side, so apply the area to all the even numbers (2,4,6)

40*3= 120 inches