Question

There are 20 people in a singing group. The mean age of 12 of the members is 18 years. The mean age of the remaining 8 is 23 years. What is the mean age of the 20 members of the singing

Answer 1

$Total \: members \: in \: singing \: group = 20$

$i ) Mean \:age \:of \: 12 \: of \:the \: members =18$

$Sum \: of \: ages \:of \: 12 \: members \\= 12 \times 18 \\= 216 \: --(1)$

$ii ) Mean \:age \:of \: 8 \: of \:the \: members =23$

$Sum \: of \: ages \:of \: 8\: members \\= 23 \times 8 \\= 184 \: --(2)$

$\red{ mean \:age\: of\: the\: 20\: members\:}\\\red{ of\: the\: singing}\\ = \frac{ (1) + (2) }{20} \\= \frac{216 + 184}{20} \\= \frac{400}{20} \\= 20$

Therefore.,

$\red{ mean \:age\: of\: the\: 20\: members\:}\\\red{ of\: the\: singing}\green { = 20 }$

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