Answer:
90 days.
Step-by-step explanation:
dy/dt = - 0.0032y
dy = -0.0032y dt
dy/y = -0.0032 dt
Integrating:
ln y = -0.0032t + c where c is some constant
y = e^(-0032t) + e^c
y = A e^(-0032t) where A is a constant.
At time 0 we can let y = 1 so in that case A = 1
When there is 0.75 of y left:
0.75 = e^-0032t
ln 0,75 = -0032 t
t = ln 0.75 / -0032
t = 90.
Answer:
idk just google it :)
Step-by-step explanation:
1. google it
The pens were 20% off of the original price
The answer would be d.
397.9
