You look behind the stove and discover a slice of bread that you misplaced several weeks ago. Needless to say, it is covered with mold. Since the mold started growing, the area it has covered has doubled each day. By the end of the 8th day, the entire surface of the bread is covered. When was the bread half-covered with mold?

On the 7th day.

Step-by-step explanation:

The mold doubles, so on the 7th day, the mold would be half-there.

I used the 8th day's description to figure this out.

30 units^2

step-by-step explanation:

area is l × w

the length is 3

and the width is 10

3 × 10= 30 units squared

6mm^3 or .6cm^3

      216

      /   \

  36     6

  /   \     /

6     6   6

factor trees are nice.