Out of 5,000 of the app's deliveries, about…

Out of 5,000 of the app's deliveries, about how many take more than 46 minutes?

Question 61

MediumOriginal question

A food-delivery app's delivery times are normally distributed with mean 40 minutes and standard deviation 8 minutes. (Take $P(0 < Z < 0.5) = 0.1915$ , $P(0 < Z < 0.75) = 0.2734$ , $P(0 < Z < 1.645) = 0.45$ and $P(0 < Z < 2) = 0.4772$ .)

Out of 5,000 of the app's deliveries, about how many take more than 46 minutes?

1{,}133

Correct answerYour answer

1{,}367

Correct answerYour answer

2{,}266

Correct answerYour answer

3{,}867

Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer A

Correct answer: A

22.66% of deliveries take more than 46 minutes.
$0.2266 \times 5{,}000 = 1{,}133$ .

Worth noting

1,367 uses 27.34%, the share between 40 and 46 minutes.

Concept: A count from a share
Typical timeTypical: 120 s
Your timeYours: —

The rule this testsUsing the normal distribution

Practise this chapter →

Ten questions from Normal Distribution, at your own pace.

Practise this chapter →

Ten questions from Normal Distribution, at your own pace.

Out of 5,000 of the app's deliveries, about how many take more than 46 minutes?

Question 61

Explanation