Answer:
175
Step-by-step explanation:
If the first term is 64 and the common ratio is 0.75, then
a(n) = 64*0.75^(n - 1).
Thus, a(2) = 64*(0.75)^(2-1) = 64*(0.75) = 48, and
a(3) = 36, and
a(4) = 27
The sum of the first 4 terms is 64 + 48 + 36 + 27 = 175
