The mean length of 9 childrens' big finger is 6.8cm. The mean length of 3 adults' big finger is 11cm.
What is the mean length (rounded to 2 DP) of these 12 people's big finger?

The mean length of these 12 people's big finger is of 7.85 cm.

Step-by-step explanation:

Mean value:

Sum of the values of all observations divided by the number of observations.

In this question:

9 + 3 = 12 total observations

Sum:

So

The mean length of these 12 people's big finger is of 7.85 cm.

d. is the correct answer

step-by-step explanation:

use the power rule  

( a b ) n = a n b n

to distribute the exponent.

apply the product rule to  

3 x 2 y 3 . ( 3 x 2 ) 2 ( y 3 ) 2

apply the product rule to  

3 x 2 . 3 2 ( x 2 ) 2 ( y 3 ) 2

raise  

3

to the power of  

2 . 9 ( x 2 ) 2 ( y 3 ) 2 multiply the exponents in   ( x 2 ) 2

.

apply the power rule and multiply exponents,  

( a m ) n = a m n . 9 x 2 ⋅ 2 ( y 3 ) 2

multiply  

2   by   2 . 9 x 4 ( y 3 ) 2

multiply the exponents in  

( y 3 ) 2 .

apply the power rule and multiply exponents,  

( a m ) n = a m n . 9 x 4 y 3

⋅

2

multiply  

3   by   2 . 9 x 4 y 6

step-by-step explanation: