# Example 5 - Chapter 13 Class 8 Direct and Inverse Proportions

Last updated at Nov. 12, 2018 by Teachoo

Last updated at Nov. 12, 2018 by Teachoo

Transcript

Example 5 The scale of a map is given as 1:30000000. Two cities are 4 cm apart on the map. Find the actual distance between them. Given, Scale of map is 1:30000000 This means that 1 cm on map is actually 3,00,00,000 cm distance Let’s first convert 3,00,00,000 cm into km 3,00,00,000 cm = 3,00,00,000 × 1/100 m = 3,00,000 m (As 1 m = 100 cm) = 3,00,000 × 1/1000 km = 300 km So, 1 cm on map is 300 km actual distance We need to find actual distance if distance in map is 4 cm Let actual distance be y km Thus, our table looks like Now, As actual distance increases, distance in map also increases. ∴ They are in direct proportion. 1/300 = 4/𝑦 𝑦 × 1= 4 × 300 𝑦 = 1200 𝑦 = 1200 km ∴ The two cities are actually 1200 km apart.

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.