# Earth Science: The table lists the world’s 10 largest deserts.

(a) What are the mean, median and mode of the areas listed?

(b) How many times the size of the Gobi Desert is the Namib Desert?

(c) What percentage of the deserts listed are in Asia?

(d) What percentage of the total area of the deserts listed is in Asia?

**Solution:**

(a) we have to find the mean, median and mode of the areas listed.

Mean = total area of all deserts/number of deserts

Total area of all deserts = 8800000 + 1300000 + 1250000 + 850000 + 580000 + 370000 + 320000 + 310000 + 310000 + 260000

= 14350000 square km

Number of deserts = 10

Mean = 14350000/10 = 1435000 square km

Median = [(n/2)th term + (n/2 + 1)th term]/2

= [(10/2)th term + (10/2 + 1)th term]/2

= [5th term + 6th term]/2

= [580000 + 370000)/2

= 950000/2

= 475000 square km

Mode is defined as the most frequently repeated observation.

Mode = 310000 square km

(b) size of the Gobi desert = 1300000 square km

Size of the Namib desert = 310000 square km

Let the size of Gobi desert be x times the size of the Namib desert

1300000 = x × 310000

130 = x × 31

x = 130/31

x = 4.19

(c) we have to find the percentage of the deserts listed in Asia.

The deserts listed in Asia are Gobi, Takla Makan, Thar, Kara Kum and Arabian desert.

Number of deserts = 5

Total number of deserts = 10

Percentage of deserts listed in Asia = 5/10 × 100

= 500/10

= 50%

Therefore, the percentage of the deserts listed in Asia is 50%

(d) we have to find the percentage of the total area of the deserts listed in Asia.

The deserts listed in Asia are Gobi, Takla Makan, Thar, Kara Kum and Arabian desert.

Total area of deserts listed in Asia = 1300000 + 850000 + 320000 + 310000 + 260000

= 3040000 square km

Total area of all deserts listed in the table = 14350000 square km

Percentage of the total area of the deserts listed in Asia = 3040000/14350000 × 100

= 21.1%

Therefore, the required percentage is 21.2%

**✦ Try This: **The weight of a stand bag is 40 kg. In a hurry it weighed 40.9 kg. The error percentage is :

**☛ Also Check: **NCERT Solutions for Class 7 Maths Chapter 8

**NCERT Exemplar Class 7 Maths Chapter 7 Problem 138**

## Earth Science: The table lists the world’s 10 largest deserts. (a) What are the mean, median and mode of the areas listed, (b) How many times the size of the Gobi Desert is the Namib Desert, (c) What percentage of the deserts listed are in Asia, (d) What percentage of the total area of the deserts listed is in Asia

**Summary:**

(a) The mean, median and mode of the areas listed are 1435000 square km, 475000 square km and 310000 square km, (b) The size of the Gobi Desert is 4.19 times the size of Namib Desert, (c) The percentage of the deserts listed in Asia is 50%, (d) The percentage of the total area of the deserts listed in Asia 21.1%

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