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SSC Selection Post 2020 PYQ — Question 57

SSC Selection Post - Matriculation Level 2020 - 14 Nov 2020 - Shift 1 • Quantitative Aptitude • Q57

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In a class of 45 students, the ratio of the number of boys and girls is 4 : 5. The average score of boys in mathematics is 78. If the average score of all the students in the class in mathematics is 76, then what is the average score of the girls in mathematics?

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Correct answer: D

Explanation

The correct answer is option 4 i.e. 74.4.

Total students = 45

Number of boys = 494\over9 × 45 = 20

Number of girls = 45 - 20 = 25

Average score of boys = 78

Let the average of girls = x

Total average = 76

⇒ (20×78)+(25×x)45=76\frac{(20 × 78) + (25 × x)}{45} = 76

⇒ 1560 + 25x = 3420

⇒ 25x = 1860

⇒ x = 74.4