Question

How to do this question plz ​

Answer 1

Answer:

  number 4: frequency 8

  number 5; frequency 2

Step-by-step explanation:

The mean of all rolls is their sum divided by their number, which is 30. Let x and y represent the number of rolls of 4 and 5, respectively. Then the mean is  ...

  (1×6 +2×3 +3×5 +4x +5y +6×6)/30 = 3.5

This simplifies to ...

  (6 +6 +15 +4x +5y +36) = 3.5×30 . . . . . multiply by 30

  4x +5y = 42 . . . . . . subtract 63

Of course, the total number of rolls must be 30:

  6 +3 +5 +x +y +6 = 30

  x + y = 10

We can solve this system of equations by substitution, using x=10-y:

  4(10 -y) +5y = 42

  40 +y = 42

  y = 2

  x = 10 -2 = 8

The two missing numbers are 8 and 2. The frequency of 4 is 8; the frequency of 5 is 2.