Multiple choice

The average age of four students is 18.5 years if the age of class-teacher is included with them, then average increases by 20% then what will be the age of class-teacher after 8 years. चार छात्रों की औसत आयु 18.5 वर्ष है यदि उनके साथ कक्षा-अध्यापक की आयु भी शामिल कर ली जाय, तो औसत 20% बढ़ जाता है। तद्नुसार कक्षा अध्यापक की 8 वर्ष बाद आयु कितनी होगी ?

  1. 37 years/वर्ष

  2. 45 years/वर्ष

  3. 43 years/वर्ष

  4. 48 years/वर्ष
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B Correct answer
Explanation

Total age of 4 students = 18.5 × 4 = 74 years. New average = 18.5 + 20% of 18.5 = 18.5 + 3.7 = 22.2 years. Total age of 5 people (4 students + teacher) = 22.2 × 5 = 111 years. Teacher's current age = 111 − 74 = 37 years. After 8 years = 37 + 8 = 45 years.

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