Rachel, Mario and Sanjit share some money in the ratios 4:3:9 Mario receives £96.
Work out the difference between the amount received by Rachel and the amount
received by Sanjit.

£160.

Step-by-step explanation:

Mario receives 3 / (4+3+9) = 3/16 of the money.

So by proportion the total amount of money

=  96 * 16/3 = £512

So Rachel receives  4/16 = 1/4

= 512 / 4

= £128.

- and Sanjit receives 9/16

= 512 * 9/16

= £288

The difference is 288 - 128 = £160.

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.