40 apps in one minute
There are 5 sections of 12 seconds in a minute.
If he can download 8 apps every 12 seconds, then in a minute he can download 5 times as that. So 8*5 is 40.
8 apps- 12 seconds
16 apps-24 seconds
24 apps- 36 seconds
32 apps- 48 seconds
40 apps- 60 seconds/ 1 minute