The number of oscillations made by a pendulum in a given time is inversely proportional to the length of the pendulum. A certain clock with a 20-in.-long pendulum is losing 11.00 min/day. Should the pendulum be lengthened or shortened, and by how much?

Answer 1

n/t = k/L

when t = 24 * 60 = 1440
let's say n should be 1440
then
k = 20
now if n = 1440-11 = 1429
we want
1440 = 1429 (20)/L
L = 19.85