Question

A flower arrangement consists of 30 roses, each of which is either white or red. If a rose is to be selected at random from the flower arrangement, the probability that the rose selected will be white is twice the probability that it will be red. How many white roses are in the flower arrangement?

Answer 1

20

Explanation:

Given that a flower arrangement consists of 30 roses, each of which is either white or red.

Also given that Prob for rose = 2 Prob for red

Let there be y white and x red

Then we have

`x+y=30`

and
`(x)/(30) =(2y)/(30)`

Solving we get

x =20 and y =10

There are 20 white roses and 10 red roses