Concept of “Problem based on ages”–05

Question: In a certain school, 20% of students are below 8 years of age. The number of students above 8 years of age is 2/3 of the number of students of 8 years age, which is 48. What is the total number of students in the school? [एक स्कूल में 20% विद्यार्थी 8 वर्ष से कम उम्र के हैं. 8 वर्ष से ज्यादा उम्र के विद्यार्थियों की संख्या, 8 वर्ष की उम्र के विद्यार्थियों की संख्या, जो कि 48 है, के 2/3 के बराबर है.स्कूल में विद्यार्थियों की कुल संख्या क्या है?] [Ans. (e) none of these (100)]  

(a)  72       (b) 120      (c) 80       (d) 150       (e) none of these

Solution:

Detailed Explanation: Given that in a certain school, 20% of students are below 8 years of age. The number of students above 8 years of age is 2/3 of the number of students of 8 years age, which are 48.

Percentage of the number of students of 8 years of age and above 8 years of age = 100% - 20% = 80%

Since the number of students of above of 8 years of age is 2/3^rd of the number of students of 8 years of age, so their ratio is 2:3 It is also given that the number of students of 8 years of age is 48

            8 years of age ≡ 3 ≡ 48

Above 8 years of age ≡ 2

                           Sum ≡ 5 ≡? = 80

Also, 80% ≡ 80

So, 100% ≡? = 100 Ans.