White - 20 marbles
black - 30 marbles
beige - 40
there are are also purple marbles in the bag. which of the following can not be the probability of randomly selecting a purple marble from the bag ?
a. 1/10
b. 1/5
c. 2/5
d. 7/15

( give an explanation)

d

Step-by-step explanation:

The probability of not being purple is the probability of the three other colors. Suppose the number of purple marbles is x. Then we have 20+30+40+x = 90 + x marbles. Then the probability of not being purple is 90/(90+x). If this fraction can have a lowest term for some value of x, then the numerator of this lowest term must be a factor of 90.

Checking through the options, only option D has a non-factor of 90 as its numerator.

the correct is answer is a 9-sided polygon!