The four sides of a picture frame consist of two pieces selected from a populationwhose mean length is 30 cm with standard deviation 0.1 cm, and two pieces selected from a popu-lation whose mean length is 45 cm with standard deviation 0.3 cm.
(a) Find the mean perimeter

150 cm

Step-by-step explanation:

The computation of the mean perimeter is presented below:

Let us assume that

X1, X2, X3 and X4 are the four sides of a picture frame

Given

(X1 + X2) ÷ 2 = 30 cm

(X3 + X4) ÷ 2 =45 cm

Now

X1 + X2 = 60 cm

And X3 + X4 = 90 cm

So, the mean perimeter is

= X1 + X2 + X3 + X4

= 60 cm + 90 cm

= 150 cm

The standard deviation is ignored.

you can't solve x because it is 2 linear equation and you only have one equation

not sure but it may be b, as i said i'm not sure.