X - the number of pencils
y - the number of pens
She has twice as many pencils as she has pens.
Tom borrows a pen, so she has y-1 pens. Now she has ten less pens than pencils.
Set 2y and y+9 equal to each other:
She has 9 pens.
Answer:
1/2
Step-by-step explanation:
if you look at a unit circle, sin(\pi/6) is 
so cos of (\pi/6/2) would be \pi/3, and cos of (\pi/3) is 1/2
Answer:
This is the answer,the option C
Step-by-step explanation:
Answer:
The population mean is 5 volts
Step-by-step explanation:
Output voltage is assumed to be normally distributed, with standard deviation 0.25 Volts
s=0.25
n = 8
Sample mean = 
Since n < 30 and population standard deviation is unknown
So, we will use t test
Formula : 
t=-1.69
Refer the t table for p value
Degree of freedom = n-1 = 8-1 = 7
So,
P value >α
So, We are failed to reject null hypothesis
Hence The population mean is 5 volts
r = -3/4p - 18/5
(or you could put 3.6 or 3 3/5 instead of 18/5)
2 - 3/4p = 5/6r + 5
-5 -5
-3 - 3/4p = 5/6r
/(5/6) /(5/6)
-18/5 - 3/4p = r
-3/4p - 18/5 = r
