Answer:
$0.30
Explanation:
We have been given that an advertiser who uses ad scheduling has a custom bid adjustment for 9 p.m. to 12 a.m. on weeknights. The normal bid is US$0.40 and the bid multiplier is -25%.
The advertiser bidding for the given time period would be $0.40 minus 25% of $0.40.





Therefore, the advertiser bidding for 9 pm to 12 am would be $0.30.