Step-by-step explanation:
Given,
1st term (a) = 1
Common ratio (r) = -4/5
last term (l) = -
Now,
Sum (S) = (lr- a)/(r - 1) =[(4/5)³° - 1]/(-9/5)
= -0.99876206/-1.8
= 0.5548678111
Sorry bro couldn't get answer in fraction.