Answer:
(a)
(b) 17:15
Step-by-step explanation:
(a)
The roulette wheel has 32 slots (inclusive of 0 and 00)
Number of Odd Numbers between 1 to 30 =15
Since you are placing a bet that the outcome is an odd number.

(b) The actual odds against winning

Therefore, the actual odds against winning are 17:15
You would do 172 -8 and keep the i when you cancel the numbers out
Step-by-step explanation:
If you have any questions about the way I solved it, don't hesitate to ask me in the comments below ÷)
It is 1595. Put it on excel so you can better have an overview how it is done. You need 5 columns, column A-E. On column A, put 1 to 5 in rows 1 to 5. On column C, put the answers: 2, 7, 26, 101 and 400. On column D, put number 3 in all 5 rows. Back on column B, insert =sum(C1-A1) on row 1 and copy till row 5. On column E, insert =sum(B1+C1*D1) on row 1 and copy till row 5 and you will get 1595 at the end.