There are 120 people in a sport centre. 78 people use the gym.
46 people use the swimming pool.
45 people use the track.
21 people use the gym and the pool.
16 people use the pool and the track,
24 people use the gym and the track.
9 people use all three facilities,
Given that a randomly selected person uses at least two facilities, what is the probability they
use all the facilities?

43/120 ≈ 0.3583

Step-by-step explanation:

Adding up the folks who use two facilities counts the folks who use all three 3 times. So, the number who use two or more facilities is ...

 21 +16 +24 -2(9) = 43 . . . . people who use 2 or more facilities

The probability that a person chosen randomly from the 120 at the sports center uses at least 2 facilities is ...

43/120 ≈ 0.3583

The given numbers add up as follows:

 Gym only: 42

Pool only: 18

Track only: 14

Gym and Pool only: 12

Gym and Track only: 15

Pool and Track only: 7

Gym and Pool and Track: 9

No facilities: 3

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation: