The value of x is 26.6.
let's solve for x using the given information:
D=5x+2
CR=39
AR=87
The formula for the arithmetic mean (AR) is the sum of all values divided by the count of values. In this case, the count of values is 3 (since there are three terms: (D, CR, and AR).
So, let's set up the equation using the arithmetic mean formula:
AR= Sum of values/ Count of values
Given that the values are CR, and AR:
AR= D+CR+AR/ 3
Plugging in the known values:
87= (5x+2)+39+87/3
Now, let's solve this equation to find x:
Multiply both sides by 3 to get rid of the denominator:
3∗87=(5x+2)+39+87
261=5x+2+39+87
Combine constants:
261=5x+128
Subtract 128 from both sides:
5x=261−128
5x=133
Divide both sides by 5:
x= 133/ 5
x=26.6
So,
x=26.6 when D=(5x+2), CR=39, and AR=87.