For a given frequency distribution,assumed mean $A = 25$,$\Sigma f_{i} d_{i} = 120$ and $\Sigma f_{i} = 140$. Then,the mean $\bar{x} = \dots$

The mean of the first ten natural numbers is ........

Find the mean of the distribution:

Class	$1-3$	$3-5$	$5-7$	$7-10$
Frequency	$9$	$22$	$27$	$17$

The median of the following frequency distribution is $28.5$ and the total frequency is $60$. Find the missing frequencies $x$ and $y$.

Class	$0-10$	$10-20$	$20-30$	$30-40$	$40-50$	$50-60$
Frequency	$5$	$x$	$20$	$15$	$y$	$5$

In a maths test taken by $35$ students,the average score of $15$ girls is $10$ and that of $20$ boys is also $10$. Which of the following can be calculated based on the data we have?

The times,in seconds,taken by $150$ athletes to run a $110\, m$ hurdle race are tabulated below:

Class (seconds)	$13.8-14.0$	$14.0-14.2$	$14.2-14.4$	$14.4-14.6$	$14.6-14.8$	$14.8-15.0$
Frequency	$2$	$4$	$5$	$71$	$48$	$20$

The number of athletes who completed the race in less than $14.6\, s$ is: