Work out (5 x 10^3) x (9 x 10^7)

Step-by-step explanation:

5×10³) × (9×10^7)

= 45 × 10^10

= 4.5 × 10¹¹

(5*10^3)*(9*10^7)=4.5*10^11

Step-by-step explanation:

5*10^3=5*1000=5000

9*10^7=9*10000000=90000000

5000*90000000=5*1000*9*10000000=5*9*10000000000=45*10000000000=450000000000, or 45 with 10 0's, or 10^10

45*10^10 is not simplified, as we need a number less then 10, so we divide 10 from 45, and add 1 to the exponent, getting 4.5*10^11

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.