Maths help

plz explain......... it

1)In a group of 200. 100 are interested in music, 70 in photography and 40 in swimming .

40 are interested in both music and photography, 30 in music and swimming. 20 in photography and swimming and 10 in all the three. How many are interested in photography but not in music or swimming? 

a) 30 b) 15 c) 25 d) 20

 

2)Given the prices of 2 commodities are increased by 10% and 20% respectively and the price of another commodity is decreased by 30%.

The relative importance of 3 commodities are in the ratio 3:3:1. Find weighted price index number.

a) 80 b) 109 c) 110 d) 108.5 

Replies (1)

This is a question involving Sets. You can solve the same using Venn diagrams. You can refer your book for same. 

A sample venn diagram can be seen here  https://en.wikipedia.org/wiki/File:Venn3tab.svg

The field 111 is the number of people interested in all three. The field "110 & 111" refers number interested in A & B and so on. Fill the diagram and you will get your answer. 

 

___________

Let The prices of commodity be 100.

New prices = 110,120 and 70

Weighted Price = 330, 360 and 70 

Weighted Average Price = (330+360+70)/7 = 108.5

There might be alternative ways of solving the problem. Refer your module for same. 

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