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The average age of 40 students of a class is 16 years. After admission of 10 new students to the class, the average becomes 15 years. If the average age of 5 of the new students is 11 years, then the average age (in years) of the remaining 5 new students is:1. 112. 163. 154. 10 |
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Answer» Correct Answer - Option 1 : 11 Given: The average age of 40 students = 16 years On admission of 10 new students average = 15 years Average of 5 new students = 11 Formula used: \({\rm{Average}} = \frac{{{\rm{sum\;of\;all\;the\;values}}}}{{{\rm{number\;of\;values}}}}\) Calculation: Sum of all ages of 40 students = 40 × 16 ⇒ 640 years After admission of 10 new students, number of students now = 40 + 10 ⇒ 50 Sum of all ages after the admission of 10 new students = 50 × 15 ⇒ 750 years Sum of ages of 5 new students = 5 × 11 ⇒ 55 years Now remaining ages of 5 new students = Sum of all ages after the admission of 10 new students - Sum of all ages of 40 students - Sum of ages of 5 new students ⇒ 750 – 640 – 55 ⇒ 750 – 695 ⇒ 55 years Average of 5 new students = 55/5 ⇒ 11 Hence, the Average of 5 new students is 11. |
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