Question

Out of 8 students the average age of the first four is 12 years and the last four is 10 years find the average age of a student

Answer 1

$\large { \fcolorbox{gray}{black}{ ✔\: \textbf{Verified \: answer}}}$

• $\bf \: Average = \sf \frac{Sum \: of \: all \: observation}{Total \: no \: of \: observations}$

In the first case,

• Average age of first 4 students is 12 years

$\bf \: 12 = \sf \frac{Sum \ of\ the \ ages \ of \ the \ last\ 4 \ students}{4}$

• Sum of the ages of first 4 students = 12 x 4 = 48.

In the second case,

• Average age of the last 4 students is 10 years

$\bf 10 = \sf \frac{Sum \ of\ the \ ages \ of \ the \ last\ 4 \ students}{4}$

• Sum of the ages of the last 4 students = 10 x 4 = 40

$\small \bf \: Average \: of \: all \: 8 \: students = \tiny \: \sf \: \frac{sum \: of \: the \: ages \: of \: first \: 4 \: students \: + \: sum \: of \: the \: ages \: of \: last \: 4 \: students}{total \: number \: of \: students}$

• Average = (48 + 40)/8
• Average = 88/8 = 11

Answer 2

Answer:

Average = (48 + 40)/8.

Average = 88/8 = 11.

Hence, the average age of each student is 11 years.

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