Asian rhinos are threatened — Who can run faster, Rhinos or Usain Bolt?

Grade level: 4 – 6th grades

Math skills: Speed

Related Environmental issues: Biodiversity / Deforestation

Javan rhinos, or Asian rhinos, are one of the most endangered animals with only about 60 indivisuals.

Rhinos can run at the speed of 50 km per hour. Usain Bolt ran 100 meters at 9.58 seconds.  Who can run faster? Explain.

Answer: Rhinos

50 km = 50,000 m

50,000 / 100 = 500

Usain Bolt runs 50km in 

[9.58 x 500 = 4,790 seconds] if he keeps running at the same speed. The running speed of rhinos is 50km per 3,600 seconds (=1hour) while that of Usain Bolt is 50km per 4,790 seconds.  Rhino can run about 1.3 times faster than Usain Bolt. 

(Usain Bolt’s running speed is 37.5 km per hour.)

“Once the most widespread of Asian rhinos, Javan rhinos are now listed as critically endangered. With only one known population in the wild, it is one of the world’s rarest large mammals.

There are between 58 and 68 in the wild, with none living in captivity. The rhinos are often poached for their horns, although loss of habitat, especially resulting from the Vietnam War, has also contributed to their decline.

The only population of Javan rhinos can be found in Ujung Kulon National Park on the south-western tip of Java, Indonesia. The only other population, in Vietnam, was wiped out in 2010.” 

(Source: Wanderlust, 2020 :

Factful Environmental Math Problems (2020)

Just published and now available from Amazon  (paperback)

About this book

The objective of Factful Environmental Math Problems is to cultivate our young people’s skills to analyze and evaluate fact-based data for understanding our world, while improving their math skills and critical thinking skills.

With the rise of the Internet and new technology, building skills to analyze and evaluate fact-based data becomes increasingly important for our young people to prepare for this rapidly changing world. These skills minimize their chances of being brainwashed by false information and making uninformed decisions and ultimately help develop their critical thinking skills. (Read more)

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Published: March 26, 2020

Price: $6.25

An Effect of rapidly melting permafrost

Grade level: 6th grades

Skills: Average 

sRelated environmental issues: Climate Change

It was reported that the temperature in the Arctic is the warmest in more than 10,000 years and it resulted in rapidly melting permafrost, soil that remains frozen year round. Due to the warmer temperature, the number of thaw slumps on Banks Island in Canada increased from 63 in 1984 to 4,077 in 2019. Those researchers predict that Banks Island will have 10,000 new slumps by 2085 if current climate warming continues.  Permafrost thaw could accelerate climate warming by releasing more CO2 into the atmosphere.*

Permafrost (Climate State)

  1. Between 1984 and 2019, how many did the number of thaw slumps increase per year on average? Round to the nearest whole number.
  2. Between 2019 and 2085, according to the prediction, how many will the number of thaw slumps increase per year on average? Round to the nearest whole number. 

*Note) Permafrost is soil that remains frozen year round. Due to its frozen state, organic matter in permafrost soils experience little decomposition by soil microbes. As a result, permafrost soils in high latitude ecosystems currently store twice as much carbon as is currently present in the atmosphere. More than 50% of global terrestrial carbon is stored in permafrost regions. Permafrost thaw stimulates the microbial decomposition of soil organic matter. This decomposition results in releasing more CO2 into the atmosphere.






Answer keys

  1. 115    (4077-63) / (2019-1984) = 4014 / 35 = 114.6
  2. 90   (10000 – 4077) / (2085 – 2019) = 5923 / 66 = 89.7