Question

Two randomly chosen customers are buying laundry soap at the store. 40% of the laundry soap on the shelves is tide brand. What is the chance that only one of them purchases tide laundry soap?.

Answer 1

64%

Explanation:

Given that, the proportion of soap that is of Tide brand = 0.40

So, the proportion of soap that are not of Tide brand = 1 - 0.40 = 0.60

Now using the compliment rule,

P(at least one) = 1 - P(none) .......(i)

The probability that none of them bought Tide,

= 0.60 x 0.60 = 0.36

From eq(i)

P(at least one bought tide) = 1 - 0.36

= 1 - 0.36

= 0.64

converting to % = 64%