Answer:
Step 3 contains error.
Step-by-step explanation:
The given equation is :

Step 1.
Cross multiplying,

Step 2.
Subtract 9 from both sides

Step 3.
Cross multiplying

So, there is an error in step 3. The correct answer should be 45.
Divide the y-value by the x-value.
(1/2) / (2/5) = 1/2 x 5/2 = 5/4
Answer:
And using the normal standard distirbution or excel we got:
Step-by-step explanation:
Let X the random variable that represent the resistance for resistors of a population, and for this case we know the distribution for X is given by:
Where
and
We are interested on this probability
And the z score formula is given by:
Using this formula we got:
And using the normal standard distirbution or excel we got:
13x[4+(9+2)]
13x[4+11]
13x[15]
195