Hi I have a question about this problem I am really confuse to do it

Part A)
1500 tickets ,
7 tickets $300
1 ticket $ 2500
then expected value is
EV = ( 7•300 + 1•2500 )/ number of tickets
EV = (2100 + 2500)/8 = 575
Expected value is $575
Part B)
there are 1000 tickets
5 tickets cost 100
1 ticket cost 2000
THEN expected value is
EV = (5•100 + 1•2000) / number of tickets
. = (500 + 2000)/ 6 = 2500/6 = 417
Part C)
1500 tickets x 10 = $15000
And
1000 tickets x 10= $10000