Acertain quantity decays exponentially over time. the initial quantity at t = 0 is 25,000. the quantity decays at a rate of 5%. what is the quantity at t = 3? a. 3.125 b. 21,434.375 c. 28,940.625 d. 3,125,000.000

For this case we have an equation of the form:
 y = A * (b) ^ t
 Where,
 A: initial amount
 b: decrease rate
 t: time
 Substituting values we have:
 y = 25000 * (0.95) ^ 3
 y = 21434.375
 
 the quantity at t = 3 is:
 B. 21,434,375