Question

class mark of (30-40) and (60-70) are​

Answer 1

$i) Given \:class \: interval \: ( 30 - 40 )$

$Lower \: boundary \: of \:the \:class = 30$

$Upper \: boundary \: of \:the \:class = 40$

$\red{ Class \: mark \: of \: 30 - 40 }$

$= \green { Average \: of \: upper \: and }$

$\green { lower \: boundaries }$

$= \frac{ 30 + 40 }{2}$

$= \frac{70}{2}$

$\green { = 35}$

$\therefore \red{ Class \: mark \: of \: 30 - 40 } \green { = 35}$

$ii) Given \:class \: interval \: ( 60 - 70 )$

$Lower \: boundary \: of \:the \:class = 60$

$Upper \: boundary \: of \:the \:class = 70$

$\red{ Class \: mark \: of \: 60 - 70 }$

$= \green { Average \: of \: upper \: and }$

$\green { lower \: boundaries }$

$= \frac{ 60 + 70 }{2}$

$= \frac{130}{2}$

$\green { = 65}$

$\therefore \red{ Class \: mark \: of \: 60 - 70 } \green { = 65}$

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