Example 1 The cost of 5 metres of a particular quality of cloth is Rs 210. Tabulate the cost of 2, 4, 10 and 13 metres of cloth of the same type.
Given cost of 5 metres of cloth = ₹ 210
We need to find cost of 2, 4, 10, 13 meters of cloth
Let’s draw a table
Finding cost of 2 meters of cloth
Let the Cost of cloth = Rs y
As quantity of cloth increases, its cost also increases.
∴ Quantity and cost are in direct proportion.
5/210 = 2/𝑦
𝑦 × 5 = 2 × 210
𝑦 × 5 = 420
𝑦 = 420/5 = 84
∴ Cost of 2 metres of cloth = Rs 84
Finding cost of 4 meters of cloth
Let the Cost of cloth = Rs y
Since Quantity and cost are in direct proportion.
5/210 = 4/𝑦
𝑦 × 5 = 4 × 210
𝑦 × 5 = 840
𝑦 = 840/5
𝑦 = 168
∴ Cost of 4 metres of cloth = Rs 168
Finding cost of 10 meters of cloth
Let the Cost of cloth = Rs y
Since Quantity and cost are in direct proportion.
5/210 = 10/𝑦
𝑦 × 5 = 10 × 210
𝑦 × 5 = 2100
𝑦 = 2100/5
𝑦 = 420
∴ Cost of 10 metres of cloth = Rs 420
Finding cost of 13 meters of cloth
Let the Cost of cloth = Rs y
Since Quantity and cost are in direct proportion.
5/210 = 13/𝑦
𝑦 × 5 = 13 × 210
𝑦 = (13 × 210)/5
𝑦 = 13 × 42
y = 546
∴ Cost of 13 metres of cloth = Rs 546
Thus, our table looks like

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.