In an examination average marks obtained by the girls of a class is $85$ and the average marks obtained by the boys of the same class is $87 .$ If the girls and boys are in the ratio $4: 5,$ average marks of the whole class $(approx.)$ is closest to
$85.9$
$86.5$
$86.4$
$86.1$
A man spends on an average $Rs.\, 269.47$ for the first $7 \,months$ and $Rs.\, 281.05$ for the next $5\, months.$ Find out his monthly salary if he saved $Rs.\,308.46$ during the $year.$ (in $Rs.$)
A student finds the average of $10,2$ digit numbers. If the digits of one of the number is interchanged, the average increases by $3.6 .$ The difference between the digits of the $2 -$digit numbers is
$19$ persons went to a hotel for a combined dinner party. $13$ of them spent $Rs.\, 79$ each on their dinner and the rest spent $Rs.\, 4$ more than the average expenditure of all the $19 .$ What was the total money spent by them.
The average of $20$ numbers is $30$ and that of other $30$ numbers is $50 .$ What is the average of all the numbers.
The average weight of $4$ men $A, B, C$ and $D,$ is $67\, kg.$ The $5^{th}$ man $E$ is included and the average weight decreases by $2 \,kg$. A is replaced by $F.$ The weight of $F$ is $4 \,kg$ more than $E$. Average weight deereases because of the replacement of $A$ and now the average weight is $64\, kg.$ Find the weight of $A ?$