Fractions and probability

[Striver]

A certain manufacturer of cake, muffin, and bread mixes has 100 buyers, of whom 50 purchase cake mix, 40 purchase muffin mix, and 20 purchase both cake mix and muffin mix. If a buyer is to be selected at random from the 100 buyers, what is the probability that the buyer selected will be one who purchases neither cake mix nor muffin mix?

A) 1/10
B) 3/10
C) 1/2
D) 7/10
E) 9/10

[Anurag@Gurome]

A certain manufacturer of cake, muffin, and bread mixes has 100 buyers, of whom 50 purchase cake mix, 40 purchase muffin mix, and 20 purchase both cake mix and muffin mix. If a buyer is to be selected at random from the 100 buyers, what is the probability that the buyer selected will be one who purchases neither cake mix nor muffin mix?

A) 1/10
B) 3/10
C) 1/2
D) 7/10
E) 9/10

Total = Cake mix + Muffin mix - Both + Neither
So, 100 = 50 + 40 - 20 + Neither
Hence, Neither = 30

Hence, required probability = 30/100 = [spoiler]3/10[/spoiler]

The correct answer is B.

[karthikpandian19]

A certain manufacturer of cake, muffin, and bread mixes has 100 buyers, of whom 50 purchase cake mix, 40 purchase muffin mix, and 20 purchase both cake mix and muffin mix. If a buyer is to be selected at random from the 100 buyers, what is the probability that the buyer selected will be one who purchases neither cake mix nor muffin mix?

A) 1/10
B) 3/10
C) 1/2
D) 7/10
E) 9/10

Refer the Figure:

Answer is B