Andrea has 5 bags with 2 marbles in each bag. Kori has 3 bags with 2 marbles in each bag.
How many more marbles does Andrea have?

4 more marbles

Step-by-step explanation:

Andrea in total, has 10 marbles since 5*2 is 10

Kori in total, has 6 marbles since 3*2 is 6

Subtract 10 by 6 is 4

10-6=4

4 marbles

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

1) 2/5

2) zero=0/1

3) zero=0/2

4) -4/5

5) undefined=3/0