Answer:
0.258819045...
Step-by-step explanation:
just plug it into a calculator
<u>Number of terms = 48</u>
<u>common difference = 1.5</u>
This question involves the concept of Arithmetic Progression.
- The formula for sum of an arithmetic progression series with first and last term given is;
=
(a + l)
where;
a = first term
l = last term
n = number of terms
- From the given sequence, we see that;
first term; a = 4
last term; l = 76
Sum of A.P;
= 1920
- Plugging in relevant values into the sum of an AP formula, we have;
1920 =
(4 + 76)
simplifying this gives;
1920 = 40n
n = 1920/40
n = 48
- Formula for nth term of an AP is;
=
+ (n - 1)d
where;
is first term
d is common difference
n is number of term
is the nth term in question
the 48th term is 76
Thus;
76 = 4 + (48 - 1)d
76 - 4 = 47d
72 = 47d
d = 72/47
d ≈ 1.5
Thus;
Number of terms = 48
common difference = 1.5
Read more at; brainly.com/question/16935540
Answer:
sorry if wrong put b as the answer
To solve for proportion we make use of the z statistic.
The procedure is to solve for the value of the z score and then locate for the
proportion using the standard distribution tables. The formula for z score is:
z = (X – μ) / σ
where X is the sample value, μ is the mean value and σ is
the standard deviation
when X = 70
z1 = (70 – 100) / 15 = -2
Using the standard distribution tables, proportion is P1
= 0.0228
when X = 130
z2 = (130 – 100) /15 = 2
Using the standard distribution tables, proportion is P2
= 0.9772
Therefore the proportion between X of 70 and 130 is:
P (70<X<130) = P2 – P1
P (70<X<130) = 0.9772 - 0.0228
P (70<X<130) = 0.9544
Therefore 0.9544 or 95.44% of the test takers scored
between 70 and 130.