SBI PO – 2015 – 29

Question: A man bought 13 shirts of Rs. 50 each, 15 pants of Rs. 60 each and 12 pairs of shoes at Rs. 65 a pair. Find the average value of each article [एक व्यक्ति ने 50 रु की दर से 13 कमीज ख़रीदे; 60 रु की दर से 15 पैंट्स ख़रीदे और 65 रु की दर से 12 जोड़ी जूते ख़रीदे. उन सभी वस्तुओं का औसत निकालें] [Ans. (a) 58.25]                            

(a) 58.25  (b) 56.75 (c) 50.25 (d) 60.25 (e) none of these

Detailed explanation:

First Method: Let the average of all articles be 50. Since the average of 15 pants is 60, so in the group of 15 pants, there are 15 × 10 = 150 Rs are extra. And, in the group of 12 pairs of shoes, there are 12 × 15 = Rs 180 extra. So, there are a total of Rs (150 + 180) = Rs 330 extra, that is to be distributed among all the 40 articles equally. In this way, each of the article will get (Rs 330)/40, that is, Rs 8.25 additionally.

Therefore, the average = Rs (50 + 8.25) =Rs 58.25 Ans.    

First method is the best method.

Second Method: This is usual method.

Price of 13 shirts at the rate of 50 Rs/shirt = Rs 50 × 13 = Rs 650  

Price of 15 pants at the rate of 60 Rs/pant = Rs 60 × 15 = Rs 900  

Price of 12 pairs of shoes at the rate of 65 Rs/pair = Rs 65 × 12 = Rs 780  

Average of all articles = (Rs 650 +Rs 900 + Rs 780)/ (13 + 15 + 12)

Rs 2330/ 40. Therefore average = 58.25 Ans.