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. 78.5 kg and 88.4 kg, respectively, 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: A
Explanation
The correct answer is Option 1 i.e. 46.
Let initial students = x
New average = 75.4 + 0.24 = 75.64
Extra weight added = 72.9 + 73.8 + 78.5 + 88.4 = 313.6
Equation:
(75.4x + 313.6)/(x + 4) = 75.64
⇒ 75.4x + 313.6 = 75.64x + 302.56
⇒ 11.04 = 0.24x
⇒ x = 11.04 / 0.24 = 46