Answer:
- 45 regular keyboards
- 15 wireless keyboards
Step-by-step explanation:
A set of 3 regular and 1 wireless keyboard would sell for ...
3×$83 +110 = $359
For the given sales, the number of sets sold was ...
$5385/($359/set) = 15 sets
Since there are 3 regular keyboards in each set, there were 3×15 = 45 regular keyboards sold. The number of each type of keyboards sold is ...
45 regular keyboards and 15 wireless keyboards
_____
<em>Comment on this solution</em>
When a problem statement tells you the ratio of one kind of item to another, it is often convenient to group the items in that ratio and deal with the groups. Sometimes, there will be a few missing or left over, for example "10 more than 3 times as many." In those cases, you can make an adjustment to the total and still deal with the groups. (Any equations you might write will effectively do this same thing.)
Answer:

Step-by-step explanation:
To factor the expression
you need to know its roots.
First find the discriminant of this quadratic polynomial:

Then the roots of the expression
are

Now the factored form is

Let's set the first angle as x, the second angle is then 4x, and the third angle is (x+4x)+15, which is 5x+15
the three angles make a sum of 180: x+4x +5x+15=180
10x=165
x=16.5
the second angle is 4x=4*16.5=66
Answer:
107.20 euros.
Step-by-step explanation:
Let the amount she had initially be x euros.
Then we have the equation:
x - 0.40x - 0.35x = 26.80
x - 0.75x = 26.80
0.25x = 25.80
Multiply both sides by 4:-
x = 107.20 euros.