A square box is filled with two layers of identical square pieces of chocolate. Kirill had eaten all 20 pieces in the upper layer along the walls of the box, how many pieces of chocolate are left in the box?

52.

Step-by-step explanation:

Since it is a square box, along the walls has

20 chocolates, only a 6x6 has 20 along the walls.

So 36+36 would be 72 and 72 - 20 is 52.

x > 1.3

step by step:

8.5−0.9x> 9.8−1.9x

step 1: simplify both sides of the inequality.

−0.9x+8.5> −1.9x+9.8

step 2: add 1.9x to both sides.

−0.9x+8.5+1.9x> −1.9x+9.8+1.9x

1x+8.5> 9.8

step 3: subtract 8.5 from both sides.

1x+8.5−8.5> 9.8−8.5

1x> 1.3

step 4: divide both sides by 1.

1x/1 > 1.3/1