The average marks obtained by the students in a class are $$43.$$ If the average marks obtained by $$25$$ boys are $$40$$ and the average marks obtained by the girl students are $$48,$$ then what is the number of girl students in the class ?
A.
$$15$$
B.
$$17$$
C.
$$18$$
D.
$$20$$
Answer :
$$15$$
Solution :
$$\eqalign{
& {\text{Let Number of girls student be }}x \cr
& {\text{Sum of marks}}\, = 25 \times 40 + x \times 48 \cr
& {\text{Total students}} = 25 + x \cr
& \therefore \,43 = \frac{{25 \times 40 + x \times 48}}{{x + 25}} \cr
& \Rightarrow 43x + 43 \times 25 = 25 \times 40 + x \times 48 \cr
& \Rightarrow 5x = 3 \times 25 \cr
& \Rightarrow x = 15 \cr} $$
Releted MCQ Question on Statistics and Probability >> Statistics
Releted Question 1
Select the correct alternative in each of the following. Indicate your choice by the appropriate letter only.
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