{"id":90555,"date":"2025-06-01T10:30:56","date_gmt":"2025-06-01T10:30:56","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=90555"},"modified":"2025-06-01T10:30:56","modified_gmt":"2025-06-01T10:30:56","slug":"the-average-age-of-the-boys-in-a-class-is-12-years-the-average-age-of","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/the-average-age-of-the-boys-in-a-class-is-12-years-the-average-age-of\/","title":{"rendered":"The average age of the boys in a class is 12 years. The average age of"},"content":{"rendered":"

The average age of the boys in a class is 12 years. The average age of the girls in the class is 11 years. There are 50% more girls than boys in the class. Which one of the following is the average age of the class (in years)?<\/p>\n

[amp_mcq option1=”11.2 years” option2=”11.4 years” option3=”11.6 years” option4=”11.8 years” correct=”option2″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CAPF – 2020<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
11.4 years<\/section>\n
The average age of the class is the weighted average of the average ages of boys and girls, where the weights are the number of boys and girls.<\/section>\n
Let $N_B$ be the number of boys and $N_G$ be the number of girls.
\nAverage age of boys ($A_B$) = 12 years.
\nAverage age of girls ($A_G$) = 11 years.
\n$N_G$ is 50% more than $N_B$, so $N_G = N_B + 0.50 N_B = 1.5 N_B$.
\nThe total sum of ages of boys is $N_B \\times A_B = 12N_B$.
\nThe total sum of ages of girls is $N_G \\times A_G = 11N_G = 11(1.5N_B) = 16.5N_B$.
\nThe total sum of ages in the class is $12N_B + 16.5N_B = 28.5N_B$.
\nThe total number of students is $N_B + N_G = N_B + 1.5N_B = 2.5N_B$.
\nThe average age of the class is $\\frac{\\text{Total sum of ages}}{\\text{Total number of students}} = \\frac{28.5N_B}{2.5N_B} = \\frac{28.5}{2.5} = \\frac{285}{25}$.
\n$\\frac{285}{25} = \\frac{57 \\times 5}{5 \\times 5} = \\frac{57}{5} = 11.4$.
\nThe average age of the class is 11.4 years.<\/section>\n","protected":false},"excerpt":{"rendered":"

The average age of the boys in a class is 12 years. The average age of the girls in the class is 11 years. There are 50% more girls than boys in the class. Which one of the following is the average age of the class (in years)? [amp_mcq option1=”11.2 years” option2=”11.4 years” option3=”11.6 years” … <\/p>\n

Detailed SolutionThe average age of the boys in a class is 12 years. The average age of<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1085],"tags":[1288,1102],"class_list":["post-90555","post","type-post","status-publish","format-standard","hentry","category-upsc-capf","tag-1288","tag-quantitative-aptitude-and-reasoning","no-featured-image-padding"],"yoast_head":"\nThe average age of the boys in a class is 12 years. 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