Question

A company selling cell phones has a total inventory of 900 phones. Of these phones, 450 are smartphones and 270 are black. If 225 phones are not black and not a smartphone, how many of the phones are black smartphones

Answer 1

To find the number of black smartphones, subtract the phones that are not black and not a smartphone from the total number of phones. In this case, there are 90 black smartphones.

Step-by-step explanation:

To find the number of phones that are black smartphones, we need to subtract the number of phones that are not black and not a smartphone from the total inventory of phones.

Given that the total inventory is 900 phones, 450 are smartphones, and 270 are black, we can calculate the number of phones that are not black and not a smartphone as follows: 900 - 450 - 270 = 180.

Therefore, the number of phones that are black smartphones is 270 - 180 = 90 phones.

Answer 2

45 of the phones are black smartphones.

Step-by-step explanation:

We sould this question treating these probabilities as Venn events.

I am going to say that:

Event A: Smartphone.

Event B: Black.

450 are smartphones and 270 are black.

This means that
`A = 450, B = 270`.

225 phones are not black and not a smartphone

This means 900 - 225 = 675 are either black or a smartphone, that is,
`(A \cup B) = 675`

How many of the phones are black smartphones?

This is:

`(A \cap B) = A + B - (A \cup B)`

Considering the values we found:

`(A \cap B) = A + B - (A \cup B) = 450 + 270 - 675 = 45`

45 of the phones are black smartphones.