Answer:
Notebooks: $2.75 each; pens: $1.10 each
Step-by-step explanation:
Let n and p represent the unit cost of notebooks and the unit cost of pens.
Then 3n + 2p = $10.45, and 4n + 6p = $17.60.
Let's use elimination by addition/subtraction to find n and p.
Multiplying the first equation by -3, we get -9n - 6p = -$31.35
and then combine this with the second: 4n + 6p = $17.60
-----------------------------
Then, -5n = -$13.75
Dividing both sides by 55, we get n = $13.75 / 5, so we now know that n = $2.75. Each notebook costs $2.75.
Subbing $2.75 for n in the first equation, we get:
3($2.75) + 2p = $10.45, or
$8.25 + 2p = $10.45
Solving for p, we get p = $2.20 / 2 = $1.10.
Each pen costs $1.10.
If Jan bought 3 lamps for $23.59 each, and a sofa for $769.99, then we can add these prices together for the total amount Jan spent:
23.59 + 23.59 + 23.59 + <span>769.99 = $840.76
</span>
Now we can find out how much sales tax she owes by multiplying the total cost by the sales tax rate:
$840.76 x 7.5% = <span>840.76 x 0.075 = $63.06
</span>
Therefore the answer is B. $63.06
Answer:
7
Step-by-step explanation:
(x,y)
The first term is a = 72
The common ratio is r = 1/6.
We multiply each term by 1/6, which is the same as dividing each term by 6.
To find r, divide any term you want over the previous term
r = 12/72 = 1/6
r = 2/12 = 1/6
etc.
Now use the infinite sum formula to find S
S = infinite sum
S = a/(1-r) ... see note below
S = 72/(1-1/6)
S = 72/(6/6 - 1/6)
S = 72/(5/6)
S = (72/1) divided by (5/6)
S = (72/1)*(6/5)
S = (72*6)/(1*5)
S = 432/5
S = 86.4
Answer: 86.4
note: this infinite sum formula only works if -1 < r < 1. In the case of r = 1/6 = 0.167 (approx), this r value is between -1 and 1.
