Step-by-step explanation:
the angle CDB is the supplementary angle to 9x+10 (angle ADC).
that means they stand together for 180°. as all angles around a single point on one side of a line are together always 180°.
and then, the sum of all angles in a triangle is always 180°.
so,
CDB + (4x + 10) + 50 = 180
CDB = 180 - (9x + 10) = 180 - 9x - 19 = 170 - 9x
therefore,
(170 - 9x) + (4x + 10) + 50 = 180
170 - 9x + 4x + 10 + 50 = 180
-5x = -50
5x = 50
x = 10
angle CDB = 170 - 9x = 170 - 90 = 80°
Answer:
I think its B and E
Step-by-step explanation:
Hope it helps
Answer:
So the answer is
Step-by-step explanation:
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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 =