The oscillation period of a load suspended on a long string is 3 seconds. How many vibrations will this load make in 2 minutes?

We translate the values from given to SI:
t = 2 minutes = 2 * 60 = 120 s.
The oscillation period is a period of time during which the body returns to the same point from which it began its movement.
T = t / n, where n is the number of oscillations, t is the time during which the body made these oscillations.
Let us express the number of oscillations from this expression:
n = t / T
Substitute the numerical values and determine the number of oscillations:
n = t / T = 120/3 = 40
Answer: the body will make 40 vibrations in the allotted time of 2 minutes.