Answer:
X=7 and y=6
Step-by-step explanation:
Y=-2x + 20.......eq(i)
6x-5y=12.....eq(ii)
Now, putting y= - 2x +20 in eq (ii)
6x - 5(-2x + 20)=12
6x + 10x - 100 = 12
16x=12+100
X=112 /16
X=7
Then, putting x=7 in eq (i)
Y=-2*7 +20
=-14 +20
=6
Answer:
45
Step-by-step explanation:
Assuming this is a trapezoid,

Answer: 
Step-by-step explanation:
The confidence interval for population mean is given by :-

Given : Sample size : n= 35 , large sample (n>30)
Mean difference : 
Standard deviation : 
Significance level : 
Critical value : 
Now, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students will be :-

Hence, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students = 
Answer:
80
Step-by-step explanation:
80 * 20% = 16
then 16 is 20% of 80