state true or false. The cost of articles varies directly as the number of articles.
(More aricles ,more cost).(Less articles .less cost).

cost is directly proportional to the number of articles.

20 articles cost ₹ 100. What is the cost of 1 article ?

If 40 articles cost Rs. 180, the cost of 18 articles is:

There are three house-hold articles. The cost of the first article is two-fifth the cost of the third article and the cost of the third article is twice the cost of second article. If the total cost of the three articles is Rs 228, then find the cost of the first article (in Rs)

If 20 articles cost ₹180, the cost of 15 articles is:

A shopkeeper sold certain articles. Cost price of each article and the number of articles sold are given below. Calculate the cost of libing index for the year 2006 taking 1999 as the base year (approximately).