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# A number is selected at random from the numbers 1 to 30 inclusive. What is the p...

### Question

A number is selected at random from the numbers 1 to 30 inclusive. What is the probability that it is divisible by 2 or 5?

### Options

A) 19/30

B) 3/5

C) 3/10

D) 7/10

The correct answer is D.

### Explanation:

From 1 - 30, there are 30 numbers, 15 numbers divisible by 2, 6 numbers divisible by 5
Pr(Divisible by 2) = $$\cfrac{15}{30} = \cfrac{1}{2}$$
Pr(Divisible by 5) = $$\cfrac{6}{30} = \cfrac{1}{5}$$
Pr(Divisible by 2 or 5) = $$\cfrac{1}{2} + \cfrac{1}{5} = \cfrac{7}{10}$$

## Dicussion (1)

• From 1 - 30, there are 30 numbers, 15 numbers divisible by 2, 6 numbers divisible by 5
Pr(Divisible by 2) = $$\cfrac{15}{30} = \cfrac{1}{2}$$
Pr(Divisible by 5) = $$\cfrac{6}{30} = \cfrac{1}{5}$$
Pr(Divisible by 2 or 5) = $$\cfrac{1}{2} + \cfrac{1}{5} = \cfrac{7}{10}$$