Base current of an n-p-n transistor when 80% of the electrons reach the collector (collector current 28 mA)

The same question, asked 2 times: 14 May 2024 S2, 18 Apr 2026 S2. Every wording below, oldest first.

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Question 1
14 May 2024 S2
45 $In an n-p-n transistor, the collector current is 28 mA. If 80% of electrons reach the collector, its base current in mA is$
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Question 2
18 Apr 2026 S2
148 $In an NPN transistor, the collector current is 28 mA. If 80% electrons reach the collector, its base current in mA is$
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