# When did the number of Coronavirus cases start increasing in the US?

Skills: Line graphs, ratio (fraction), and division

Related environmental issues: Others

Coronavirus has infected more than 1.6 million people in 211 countries as of April 10, 2020. The three figures below show some of the impacts that it’s had on people.

The line graph below shows the number of confirmed coronavirus cases in the United States since February 3, 2020.

1. During which period did the number of confirmed cases start increasing?

A)During 2/23 – 3/4

B) 3/4 – 3/14

C) 3/14 – 3/24

D) 3/24 – 4/3

2. During which period did the number of confirmed cases increase more, during 3/14 – 3/24 or 3/24 – 4/3 ?

3. Around how many confirmed cases does the United States have now?

A) 340,000 cases

B) 480,000 cases

C)  520,000  cases

As many countries introduced travel restrictions not to spread the Coronavirus, the number of airplanes in the air decreased.

The figure below compares the number of airplanes that used the London Heathrow Airport, one the busiest airports in the world, on March 27, 2019 and March 25, 2020.

4. Which fraction shows the ratio of the number of airplanes at the London Heathrow Airport on March 25, 2020 to that on March 27, 2019?

A) 1/2

B) 1/3

C) 2

D) 3

As more people stay at home and work from home, workers depend more on video calls and instant messaging.

The bar graph below shows the number of business instant messaging sent by the average Slack app user for 5 days during February and March in New York. Slack is a business instant messaging app.

5. How many instant messages were sent by the average Slack user in NY in a day during February? Round to the nearest whole number.

6. How many instant messages were sent by the average Slack user in NY in a day during March?

7. How many more instant messages were sent by the average Slack user in NY in a day in March than in February?

The structure of the figure was modified.

1. C
2. During 3/24 – 4/3
3. B
4. B
5. 43
6. 54
7. 11

### Factful Environmental Math Problems (2020)

Just published and now available from Amazon  (paperback)