The average weight of the students in a group was 75.4 kg. Later on, four students having weights 72.9 kg, 73.8 kg, 79.5 kg and 87.4 kg joined the group. As a result, the average weight of all the students in the group increased by 0.24 kg. What was the number of students in the group, initially?
Show answer & explanation
Correct answer: C
Explanation
Correct Answer is option 3 i.e. 46
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Application |
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Given: Initial average = 75.4 kg Increased average = 75.4 + 0.24 = 75.64 kg Suppose the number of students = x Sum of weights of x students = 75.4x Now, Four students having weights 72.9, 73.8, 79.5 and 87.4 kg joined the group: 75.4x + 72.9 + 73.8 + 79.5 + 87.4 = (x + 4) × 75.64 ⇒ 75.4x + 313.6 = 75.64x + 302.56 ⇒ 75.64x – 75.4x = 313.6 – 302.56 ⇒ 0.24x = 11.04 ⇒ x = 46 Hence, number of students in the group, initially = 46 |