Answer:
3/20
Step-by-step explanation:
By question it's given that ,
And we need to find out the value of a/c .For that Multiply both of them , we have ;
<u>Hence</u><u> the</u><u> </u><u>required</u><u> answer</u><u> is</u><u> </u><u>3/</u><u>2</u><u>0</u><u> </u><u>.</u>
21 students because if 6 represents 30% u add 6 two more time which equals 18 and 90% then u add 3 more because it is half of 6. when u add 3 more u will get 21 and 100%

It looks like your first selection (a) is appropriate.