The average score of 42 students in a test is 69. The ratio of the number of boys to that of girls is 10 : 11. The average score of the boys is 20% more than that of the girls. The average score of the boys is:
Answer & explanation
Correct answer: option 4
Ratio of No. of Boys to Girls = 10 : 11
20% = +\(\frac{1}{5}\)
Ratio of average score ⇒ Boys : Girls = 6 : 5
Now,
Accordingly average of all students = \(\frac{(6 × 10) + (5 × 11)}{10 + 11}\) = \(\frac{115}{21}\)
ATQ,
\(\frac{115}{21}\)R = 69
1R = 69 × \(\frac{21}{115}\)
Average score of Boys = 6R = 6 × 69 × \(\frac{21}{115}\) = 75.6