Question

the stem - and - leaf plot below gives the gas mileages (in miles per gallon) for 15 new cars. use the plot to answer the questions that follow.
gas mileage (miles per gallon)
1 | 5
2 | 0 3 7
3 | 3 3 3 3 4 4 4 6 7
4 | 0 7
5 | 7 8
key: 1|5 means a gas mileage of 15.
(a) what is the lowest gas mileage overall?
(b) how many cars have a gas mileage in the 30s?
(c) what is the lowest gas mileage in the 20s?

Explanation:

Part (a)

Step1: Understand stem - leaf plot

In a stem - leaf plot, the stem is the left - most digit(s) and the leaf is the right - most digit. The key \(1|5\) means 15. So we look at all the data points represented by the stem - leaf plot. The stems are 1, 2, 3, 4, 5. The smallest stem is 1, and the leaf for stem 1 is 5. So the data point is 15.

Step1: Identify stem for 30s

The stem for the 30s is 3.

Step2: Count leaves for stem 3

The leaves for stem 3 are 3, 3, 3, 3, 4, 4, 4, 6, 7. Let's count them: 1 (first 3) + 1 (second 3) + 1 (third 3) + 1 (fourth 3) + 1 (first 4) + 1 (second 4) + 1 (third 4) + 1 (6) + 1 (7) = 9.

Step1: Identify stem for 20s

The stem for the 20s is 2.

Step2: Find the smallest leaf for stem 2

The leaves for stem 2 are 0, 3, 7. The smallest leaf is 0. So the gas mileage is \(20 + 0=20\).

Answer:

15

Part (b)