A certain quantity decays exponentially over time. The initial quantity at t = 0 is 1,000. The quantity decays at a rate of 2%. What is the quantity at t = 4?
A. 0.00016
B. 1.6000
C. 903.9208
D. 922.3682

D: 922.3682

Step-by-step explanation:

First you take 1000 and subtract 20 from it.( 2% of 1000 = 1000x0.02x2=20).

You could do this on a calculator by entering 1000 and then subtracting 2% by clicking minus then, 2 then percent, then equals. you get 980. do the same to 980. (click minus, then 2, then percent, then equals). you get 960.4. do the same to 960.4. you get 941.192. do the same one more time since it says t=4  and you get 922.36816 which rounded to the nearest ten-thousandths is 922.3682.

hope this helped!

rick has $1400 and sally has $1500

step-by-step explanation:

to find amount of money rick has after 10 years :

principal = $1000 , time = 10 years , rate = 4% annually

to find amount of money sally has after 10 years :

her friend gives to pay her $50 per year, therefore money she has after 10 years = 50 × 10 = $500

also, sally gets $1000 after 10 years,

therefore, total amount of money sally has after 10 years = 500 + 1000 = $1500

so, after 10 years : rick has $1400 and sally has $1500