Math Q: thirty students bought pennants for the football game. Plain pennants cost $4 each...see details?

Question

thirty students bought pennants for the football game. Plain pennants cost $4 each and the fancy ones cost $8 each. If the total bill was $168, how many students bought the fancy pennants?

i was supposed to make a chart for this
number [times] price = cost
fancy F[thats a variable]
plain

please dont just give me the answer, explain so that i can do the rest of my hw!!!!

Answer 1

What I would do is make a chart with "Quantity of Fancy pennants" along the left side, and "Quantity of Plain pennants" across the bottom.
As you can imagine for every fancy pennant that was bought (as you go higher on the left side) the number across the bottom will go down
You can only have a maximum of either of only 30 as that is how many student bought pendants, So the chart will look as follows;
30...A
29...A B
28...A B C
27...A B C D
26...A B C D E
25...A B C D E F
24...A B C D E F G
...
etc, etc
...
02...
01...
00...A B C D E F ... ... X Y, etc
... 0 1 2 3 4 5 6 ... ... 29 30.

this is just to give you a general idea of the shape, of the curve, and you can see the Fancy quantities on the far left side and the plan quantities on the very bottom, (the line that reads, " ... 0 1 2 3 4 5 6 ... ...29 30.")
Now you wont have "A" and "B" letters on the chart ( i just did that so you woudl see what it looks like, and coz its hard to "draw" charts in a text box)
The column with just A woudl really just have a single number in the top spot, .. that number woudl be the cost of (look at the left side, you see "30") 30 * $8, plus (look down and you see '0') 0 *$4, so in that top spot you write $240, next is the spot for Fancy = 29 and plain = 1, that is the top of the B column, so the value on the second spot woudl be (look left, 29) 29 * $8 + (look bottom, 1) 1 *$4 ... (29*8) + (1*$4) = $236.
So now you can fill out the rest of this chart going all the way down till you get to NO fancy pennants and 30 plain pennants
... and each column of the chart would have an amount in $$$ as the value for it, and sop you can use the chart to look at which one shows $168 (that is the right combination).

Note that the other answers are using a more advanced math, that you haven't reached yet, so although the answers there should be exactly what you see on your chart when you complete it ... don't try to understand those equations just yet.

Answer 2

This problem is much more easily dealt with algebraically than by any sort of charting technique. We have:
4P + 8F = 168; P + F = 30. Divide first relation by 4 to get P + 2F = 42; compare with the second relation to see that F = 12; so P = 18 and we're done.

Answer 3

12 students bought the fancy pennants.

Set up two equations:

4x + 8y = 168 (# who bought plain * price + # fancy * price)
x + y = 30 (total # of students who bought pennants)

Slove the system of equations

4x + 8y = 168
-4x - 4y = 120

4y = 48
y = 12

Answer 4

4x+8(30-x)=168
4x+240-8x=168
-4x=168-240
-4x=-72
x= -72/-4
x=18
30-18=12
18 $4 plan + 12 $8 fancy = $168

Answer 5

Okay, this question does not make sense because you didn't give me enough information. You need to know how many plain pennants you sold before you solve the problem. Sorry I couldn't help you. :(

Answer 6

21 because if u divide u''ll get 21 8s will fit into 168 you can also so 20 fancy & 2 normal pendents or just 42 normal etc, there are may different possible outcomes that is what u hav to make tthe chart out of hope i helped!