Question

Suppose that 1/2 of the children in preschool are scared of snakes, 1/3 are scared of spiders, and 1/12 are scared of snakes and spiders.

1. What fraction of those who are scared of spiders are also scared of snakes?

A) 1/2
B) 1/3
C) 1/4
D) 1/6

2. What fraction of those who are scared of snakes are also scared of spiders?

A) 1/2
B) 1/3
C) 1/4
D) 1/6

Answer 1

1. C)

2. D)

Explanation:

We know that:

1/3 is afraid of spiders

1/12 fears spiders and snakes

Then, the proportion of children who fear spiders and also snakes is calculated as:

`((1)/(12))/((1)/(3)) = (1)/(4)`

Option C)

Of the 1/3 of children who fear spiders, 1/4 of them also fear snakes.

Now:

1/2 is afraid of the serientes

1/12 fears spiders and snakes

Then, the proportion of children who fear spiders and also snakes is calculated as:

`((1)/(12))/((1)/(2)) = (1)/(6)`

Option D)

Of the 1/2 of children who fear snakes, 1/6 of them also fear spiders