A frequency table of marks of 30 students is: $10$-$\,2$, $20$-$\,5$, $30$-$\,8$, $40$-$\,7$, $50$-$\,?$.…
A frequency table of marks of 30 students is: $10$-$\,2$, $20$-$\,5$, $30$-$\,8$, $40$-$\,7$, $50$-$\,?$. What is the missing frequency for class $50$?
$5$
$6$
$7$
$8$
Solution
Sum of given frequencies $= 2+5+8+7 = 22$. Missing frequency $= 30-22 = 8$.