if the blackout begins at 5:20 pm and ended at 7:05 pm how long did the black out last?

[math_celebrity]

if the blackout begins at 5:20 pm and ended at 7:05 pm how long did the black out last?

add 2 hours, and we get:
7:20

Subtract 15 minutes, and we get:
7:05

2 hours - 15 minutes = 1 hour and 45 minutes