Answer:
The value of T₂₀ - T₁₅ is <u>-20</u>.
Step-by-step explanation:
<u>Given</u> :
<u>To</u><u> </u><u>Find</u> :
<u>Using Formula</u> :
General term of an A.P.

- >> Tₙ = nᵗʰ term
- >> a = first term
- >> n = no. of terms
- >> d = common difference
<u>Solution</u> :
Firstly finding the A.P of T₂₀ by substituting the values in the formula :






Hence, the value of T₂₀ is a + 19d.

Secondly, finding the A.P of T₁₅ by substituting the values in the formula :






Hence, the value of T₁₅ is a + 14d

Now, finding the difference between T₂₀ - T₁₅ :









Hence, the value of T₂₀ - T₁₅ is -20.

We can say that lines A and D are <em>perpendicular</em>.
Answer:
c...
Step-by-step explanation:
For margin of error to be a maximum of 3:
3 = z*(SD / sqrt(n)), where z is the z-score, SD is the standard deviation and n is the sample size.
z = 1.96 for a 95% confidence interval, and we are given SD = 15.
3 = 1.96*15/sqrt(n)
sqrt(n) = 9.8
n = 96.04 ~ 96 commercials.
1
A coefficient is the number attached to a variable (k). In front of k is an implied 1 because k*1=k. So the coefficient of the third terms is 1