Question 51

The average marks scored by $$F_{1}$$ and $$F_{2}$$ is 40 more than the average marks scored by $$F_{2}$$ and $$F_{3}$$. If the marks scored by $$F_{3}$$ is 90, then what is the marks obtained by $$F_{1}$$?

Solution

The average marks scored by $$F_{1}$$ and $$F_{2}$$ is 40 more than the average marks scored by $$F_{2}$$ and $$F_{3}$$.

$$\frac{F_1+F_2}{2}\ =40+\frac{F_2+F_3}{2}\ $$

If the marks scored by $$F_{3}$$ is 90.

$$\frac{F_1+F_2}{2}\ =40+\frac{F_2+90}{2}\ $$

$$\frac{F_1+F_2}{2}\ =\frac{80}{2}+\frac{F_2+90}{2}\ $$

$$F_1+F_2\ =80+F_2+90\ $$

$$F_1=170\ $$
Marks obtained by $$F_{1}$$ = 170

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