Answer:
72.3
Step-by-step explanation:
Given that:
The arithmetic sequence:

The first term of the sequence
= 3 since k = 0
i.e (3 + 0.26(0)) = 3
The last term of the sequence
= 6.64
i.e (3+ 0.26(14)
= (3 + 3.64)
= 6.64
Total no of terms = 15 i.e from 0 to 14
∴
The partial sum of the arithmetic sequence = 

= 72.3
Answer:
The condition are
The Null hypothesis is 
The Alternative hypothesis is
The check revealed that
There is sufficient evidence to support the claim that in a small city renowned for its music school, the average child takes at least 5 years of piano lessons
Step-by-step explanation:
From the question we are told that
The population mean is 
The sample size is n = 20
The sample mean is 
The standard deviation is 
The Null hypothesis is 
The Alternative hypothesis is
So i will be making use of
level of significance to test this claim
The critical value of
from the normal distribution table is 
Generally the test statistics is mathematically evaluated as

substituting values


Looking at the value of t and
we see that
so we fail to reject the null hypothesis
This implies that there is sufficient evidence to support the claim that in a small city renowned for its music school, the average child takes at least 5 years of piano lessons.
Let x represent the smaller angle. Then the larger one is 20+4x. Since they are complementary, their sum is 90. (All measures are degrees.)
90 = x + (20+4x)
90 = 5x +20
70 = 5x
14 = x
The smaller angle is 14°.
The larger angle is 76°.
Here you go, The answer is 8.75