f.3 數學the mean

1. Mean of a, b, c, d, e is 12

The mean of 2a, 2b, 2c, 2d, 2e

= (2a + 2b + 2c + 2d + 2e)/5

= 2(a + b + c + d + e)/5

= 2(12)

24


2. Mean

= [(2a + 4) + (2b + 4) + (2c + 4) + (2d + 4) + (2e + 4)]/5

= [5(4) + 2(a + b + c + d + e)]/5

= 4 + 2(12)

= 28


3. (x + y + z)/3 = 7

Mean

= [(x + 5) + (y + 5) + (z + 5)]/3

= [3(5) + (x + y + z)]/3

= 5 + 7

= 12