Please answer the following question by reasoning step-by-step.
Hershel has 10 betta fish and 15 goldfish in a bowl. His friend Bexley brings him 2/5 times as many betta fish and 1/3 times as many goldfish. If Hershel gifts his sister 1/2 of the fish, calculate the total number of fish he has remaining in the bowl.

17
Bexley gives Hershel 2 / 5 * 10 = 4 betta fish.

The total number of betta fish in the bowl is now 4 + 10 = 14.

He also gives Hershel 1 / 3 * 15 = 5 goldfish.

The total number of goldfish in the bowl is now 15 + 5 = 20.

Counting the betta fish and goldfish, Hershel now has a total of 14 + 20 = 34 fish.

When he gives his sister half of the fish, the remaining half is 34 / 2 = 17 fish.

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Final answer: 17