Answer: she received 21.875 hours of sleep during the 4 nights.
Step-by-step explanation:
Rosalie is following a geometric sequence(GP) by having a common rate of sleep .
as 75% or 0.75%.
Formula for a sum in GP= , where a= first term, r = common ratio, n= number of terms.
Put a= 8, r=0.75 and n =4, we get
On simplifying we get
Sum =21.875 hours
Hence, she received 21.875 hours of sleep during the 4 nights.