9514 1404 393
Answer:
$2.50
Step-by-step explanation:
The question asks for the total cost of a notebook and pen together. We don't need to find their individual costs in order to answer the question.
Sometimes we get bored solving systems of equations in the usual ways. For this question, let's try this.
The first equation has one more notebook than pens. The second equation has 4 more notebooks than pens. If we subtract 4 times the first equation from the second, we should have equal numbers of notebooks and pens.
(8n +4p) -4(3n +2p) = (16.00) -4(6.50)
-4n -4p = -10.00 . . . . . . . . . . . simplify
n + p = -10.00/-4 = 2.50 . . . . divide by the coefficient of (n+p)
The total cost for one notebook and one pen is $2.50.
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<em>Additional comment</em>
The first equation has 1 more notebook than 2 (n+p) combinations, telling us that a notebook costs $6.50 -2(2.50) = $1.50. Then the pen is $2.50 -1.50 = $1.00.
One could solve for the costs of a notebook (n) and a pen (p) individually, then add them together to answer the question. We judge that to be more work.
30+6+0.4+0.09+0.005=36.495
Answer: B and C only
Step-by-step explanation:
The temperature on a cold day starts at 0 degrees Celsius, falls 4 degrees, and rises 4 degrees
Initial temperature = 0
Temperature rise = 4
Fall in temperature = - 4
(Initial temperature + rise in temperature + fall in temperature)
Summing all : (0 + 4 - 4) = 0
carbon atom has 6 negatively charged electrons and 6 positively charged protons.
Net charge of atom :
(number of proton + number of electrons)
( 6 + (-6)) = 0
