Average weight of $25$ persons is increased by $1 \,kg ,$ when one man weighing $60\, kg$ is replaced by a new person. Weight of new person is? (in $kg$)

In a class, the average height of $35$ girls was measured $160 \,cm$. Later, on it was discovered that height of one of the girls was misread as $144\, cm ,$ while her actual height was $104 \,cm.$ What was the actual average height of the girls in the class? (in $cm$) (rounded off to two digits after decimal)

The average of $6$ numbers is $8.$ What is the $7^{th}$ number so that average becomes $10 ?$

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 $15$ minutes. The total journey is (in $km$)

The average weight of a group of $20 \,boys$ was calculated to be $89.4\, kg$ and it was later discovered that one weight was misread as $78 \,kg$ instead of $87 \,kg.$ The correct average weight is (in $kg.$)

The average monthly income of $P$ and $Q$ is $Rs.\,5050.$ The average monthly income of $Q$ and $R$ is $Rs.\,6250$ and the average monthly income of $P$ and $R$ is $Rs.\,5200.$ The monthly income of $P$ is