If mean (x) pom 15, Efx = 342 + a and N = 20 + a, find the value of a.

a = 3

Step-by-step explanation:

mean is calculated as

mean =

Here mean = 15, sum = 342 + a and count = 20 + a , then

= 15 ( multiply both sides by 20 + a )

342 + a = 15(20 + a) ← distribute

342 + a = 300 + 15a ( subtract a from both sides )

342 = 300 + 14a ( subtract 300 from both sides )

42 = 14a ( divide both sides by 14 )

3 = a

answer: for each 3 girls there is 2 boys . 3: 2

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(x3 + 6x2 + 2x - 6) • (x - 1)

step-by-step explanation:

polynomial long division :

3.2     polynomial long division

dividing :   x4+5x3-4x2-8x+6

                              ("dividend")

by         :     x-1     ("divisor")

dividend     x4   +   5x3   -   4x2   -   8x   +   6

- divisor   * x3     x4   -   x3            

remainder         6x3   -   4x2   -   8x   +   6

- divisor   * 6x2         6x3   -   6x2        

remainder             2x2   -   8x   +   6

- divisor   * 2x1             2x2   -   2x    

remainder               -   6x   +   6

- divisor   * -6x0               -   6x   +   6

remainder                     0

quotient :   x3+6x2+2x-6   remainder:   0