A = amount invested at 4%.
b = amount invested at 9%.
we know the total amount invested was $26500, thus
a + b = 26500.
whatever% of anything is just (whatever/100) * anything.
how much is 4% of a? well, is just (4/100) * a, or
0.04a.
how much is 9% of b? well, is just (9/100) * b, or
0.09b.
we know the interest yielded for both amounts adds up to $1510, thus
0.04a + 0.09b = 1510.

how much was invested at 9%? well, b = 26500 - a.
Answer:
Given:
Mean, u = 2100
A golf magazine reports the mean gain to be $2100, while the teaching professional believes the average gain is not $2100.
Here the null and alternative hypotheses would be:
Null hypothesis:
H0: u = 2100
Alternative hypothesis:
Ha: u ≠ 2100
b) Here, given the level of significance,
as 0.10. This means that:
The probability that the null hypothesis H0 is rejected when average gain is $2100 is 0.10
Answer:
300 cars must be made to minimize the unit cost
Step-by-step explanation:
Vertex of a quadratic function:
Suppose we have a quadratic function in the following format:

It's vertex is the point 
In which


Where

If a>0, the vertex is a minimum point, that is, the minimum value happens at
, and it's value is
.
The cost of producing x cars is given by:

So a quadratic equation with 
How many cars must be made to minimize the unit cost?
This is the xvalue of the vertex. So

300 cars must be made to minimize the unit cost
Full bubble at 0, then make it go right.