Five years ago,the average age of a husband and wife was $23 \text{ years}$. Today,the average age of the husband,wife,and child is $20 \text{ years}$. How old is the child in years?

Average of $a, b$ and $c$ is $11$; average of $c, d$ and $e$ is $17$; average of $e$ and $f$ is $22$ and average of $e$ and $c$ is $17$. Find out the average of $a, b, c, d, e$ and $f$?

With an average speed of $40 \, km/h$,a train reaches its destination on time. If it goes with an average speed of $35 \, km/h$,it reaches late by $15 \, \text{minutes}$. The total journey is (in $km$):

The average of $50$ numbers is $38$. If two numbers,namely $45$ and $55$,are discarded,the average of the remaining numbers is

$A$ cricketer whose bowling average is $12.4$ runs per wicket takes $5$ wickets for $26$ runs and thereby decreases his average by $0.4$. The number of wickets taken by him till the last match was:

The average marks in English of a class of $24$ students is $56$. If the marks of three students were misread as $44, 45,$ and $61$ in lieu of the actual marks $48, 59,$ and $67$ respectively,then what would be the correct average?