Answer:
Step-by-step explanation:
1 hour=60 min
7 hours=60×7=420 min
number of blink=420×13=5460
Actually, you have to find four missed terms of geometrical sequence. Denote
and r - ratio, then
.
Since
, you have that
, then
.
Now substitude r=2 in each of unknown 4 terms:
.
Answer: four geometric means between 25 and 800 are 50, 100, 200, 400.