1.

In a Joint family of 9 males and some female members, the average expenses on shopping per head per month is Rs.2300; while the average expenses on shopping by male members is Rs.1500 per head and for female members it is Rs. 3200 per head. The number of female members in the family is:1). 82). 63). 74). 9

Answer»

ACCORDING to the GIVEN information,

NUMBER of male members = 9

Let the number of female members be y.

We know that, Average = Sum of all observations/Number of observations

The average expenses on shopping by male members is Rs.1500 per head

∴ 1500 = Expense by males/9

⇒ Expense by males = 1500 × 9 = 13500

The average expenses on shopping by female members is Rs.3200per head

3200 = Expense by females/y

⇒ Expense by females = 3200y

Now, overall average expense = (Expense by males + Expense by females)/(males + females)

$(\THEREFORE 2300 = \;\frac{{13500 + 3200y}}{{9 + y}})$

⇒ 20700 + 2300y = 13500 + 3200y

⇒ 900y = 7200

⇒ y = 8

Hence, the number of female members is 8


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