Without further study, you forget things as time passes. A model of human memory gives the percentage, p, of acquired knowledge that a person retains after t weeks. The formula is p = (100 – a)e-bt + a, where a and b vary from one person to another. If a = 18 and b = 0.6 for a certain student, how much information will the student retain two weeks after learning it?

Question

54% or 43%? I keep ending up with 26%

Answer 1

(100-18)e^-.6(2) +18
24.69792538+18
= 42.6

So round up. 43%