Answer:
8640
Step-by-step explanation:
Take 2.4 hours, And 1 hour is 60 minutes, and 1 minute has 60 seconds, so 1 hour has 3600 seconds, Do one more hour and you have 7200 seconds, Now you need to add another .4 hours, .4 hours is equal to 40 minutes, so how many seconds are in 40 minutes? 1440 seconds are in 40 minutes, so add 7200 and 1440 and you get 8640.
