The following frequency distribution table shows the blood groups of $30$ students of a class. Use this table to determine the probability that a student of this class,selected at random,has blood group $AB$.

Blood group	Number of students
$A$	$9$
$B$	$6$
$AB$	$3$
$O$	$12$
Total	$30$

The record of a weather station shows that out of the past $250$ consecutive days,its weather forecasts were correct $175$ times.
$(i)$ What is the probability that on a given day it was correct?
$(ii)$ What is the probability that it was not correct on a given day?

$A$ tyre manufacturing company kept a record of the distance covered before a tyre needed to be replaced. The table shows the results of $1000$ cases.

Distance (in $km$)	less than $4000$	$4000$ to $9000$	$9001$ to $14000$	more than $14000$
Frequency	$20$	$210$	$325$	$445$

If you buy a tyre of this company,what is the probability that:
$(i)$ it will need to be replaced before it has covered $4000 \, km$?
$(ii)$ it will last more than $9000 \, km$?
$(iii)$ it will need to be replaced after it has covered somewhere between $4000 \, km$ and $14000 \, km$?

Two coins are tossed simultaneously $500$ times,and we get:
Two heads : $105$ times
One head : $275$ times
No head : $120$ times
Find the probability of occurrence of each of these events.

The percentage of marks obtained by a student in the monthly unit tests are given below:

Unit test	$I$	$II$	$III$	$IV$	$V$
Percentage of marks obtained	$69$	$71$	$73$	$68$	$74$

Based on this data,find the probability that the student gets more than $70\%$ marks in a unit test.

Fifty seeds were selected at random from each of $5$ bags of seeds,and were kept under standardised conditions favourable to germination. After $20$ days,the number of seeds which had germinated in each collection were counted and recorded as follows:

Bag	$1$	$2$	$3$	$4$	$5$
Number of seeds germinated	$40$	$48$	$42$	$39$	$41$

What is the probability of germination of
$(i)$ more than $40$ seeds in a bag?
$(ii)$ $49$ seeds in a bag?
$(iii)$ more than $35$ seeds in a bag?