Once Farid spends 15 minutes on a single level in his favorite video game, he loses a life. He has already spent 10 minutes on the level he's playing now.

0.6666 or

Step-by-step explanation:

Since this is a ratio problem we can simply use the rule of three to solve it. We need to multiply the diagonal values and divide by the remaining value to get the variable which in this case is x (how much life he has already lost)

15 minutes   <=======>   1 life

10 minutes   <=======>   x

(10 * 1) / 15 = x

10 / 15 = x

0.6666 or  = x

Finally, we can see that Farid has lost 0.6666 or in those 10 minutes

1/800 is the right answer