Try using the back of the book.
Answer:
A. 3:30.
Step-by-step explanation:
180 is 90+90 so that would put it in 3:30.
Total balls: 6 + 4 + 3 = 13
First pick green = total green / total balls = 4/13
adter picking the first ball there are 12 balls left.
Picking red = total red/ total balls left = 6/12 = 1/2
probability of picking both = 4/13 x 1/2 = 4/26 = 2/13
answer: 2/13
Here's the work:
Density = mass/volume = 129g/(5*3*2) cm^3 = 4.3 g/cm^3.