I keep getting this answer wrong please help!!

Step-by-step explanation:

They closed the 200 mile distance in 2.5 hours, so the sum of their speeds was ...

  (200 mi)/(2.5 h) = 80 mi/h

If s is the speed of the slower one, then ...

  s + (s+20) = 80

  2s = 60

  s = 30

The slower wander's speed was 30 mph; the faster one's was 50 mph.

2. True

4. True

Step-by-step explanation:

1. The number line of a dot plot would start at 1.

False. The objective of the point diagram is to show the number of times a given event is repeated, therefore the diagram should show the number of times that no mail arrived during the day

2. A dot plot would show 7 points for numbers greater than 2.

 It is true. Note that the data shows this series of numbers greater than 2.

Number Frequency

3 2

4 3

5 1

6 1

Total 7

3. The intervals on a histogram should be 0 to 2, 3 to 4, and 5 to 6.

The intervals should not necessarily have a difference of 2 units.

4. A histogram would have a maximum of 7 bars.

It's true, because there are only 7 different data types {0, 1, 2, 3, 4, 5, 6}

5. A histogram should not show a bar that includes 0 pieces of mail.

It is not true. This histogram should show a bar with 0 pieces because it must show the number of days that no mail arrived. Also in this problem 0 is defined as a class with frequency of 3