Need help on math problem Quick... Need it for test..?

Question

I have a take home test, and am stuck on this problem. I need to get this right, to pass. could someone help me solve this problem. it would be appreciated more then you know. Thank You.

An office manager has 5 cent stamps, eight cent stamps, and twenty cent stamps.
There are three times as many 20 cent stamps as five cent stamps. There are 2 fewer eight cent stamps then five cent stamps. The total value of the stamps in the collections is 2.76. Find then number of five cent stamps.

Cold anyone give me any help on solving this.

Thank You everyone. I was drawing a blank haha... you are the best!!!

Answer 1

Let x = the number of 5 cent stamps
3x = the number of 20 cent stamps
x -2 = the number of 8 cent stamps

price times number = total cost

all in cents:

5x + 20(3x) + 8(x-2) = 276

5x + 60x + 8x - 16 = 276

73x = 292

x = 4

4 five cent stamps
12 twenty cent stamps
2 eight cent stamps

that's it! good luck on your test -- try to learn this stuff, tho, because it develops your thinking power, yep!!! :)

Answer 2

Let x, y & z denote the # of 5, 8 & 20 cent stamps, respectively.
translate the given information.
1. There are three times as many 20 cent stamps as five cent stamps.
z = 3x
2. There are 2 fewer eight cent stamps than five cent stamps.
y = x - 2
3. The total value of the stamps in the collections is 2.76.
(0.05)x + (0.08)y + (0.2)z = 2.76
4. Find then number of five cent stamps.
Use substitution:
(0.05)x + (0.08)(x - 2) + (0.2)(3x) = 2.76
5x + 8(x - 2) + 20(3x) = 276
5x + 8x - 16 + 60x = 276
73x = 276 + 16
73x = 292
x = 292 / 73 = 4.

Answer 3

the answer is 4 12 20 cent stamps 4 5 cent stamps 2 8 cent stamps 2.76 cents..the answer is 4

Answer 4

f = # of five cent stamps
e = # of eight cent stamps
t = # of twenty cent stamps

There are three times as many 20 cent stamps as five cent stamps

1) t = 3f

There are 2 fewer eight cent stamps then five cent stamps.

2) e = f - 2

The total value of the stamps in the collections is 2.76

3) 5f + 8e + 20t = 276 {pennies}

Substitute for t from equation1 and for e from equation 2

3a) 5f + 8(f - 2) + 20(3f) = 276
5f + 8f - 16 + 60f = 276
73f = 292
f = 4

Answer 5

That isnt hard. 12 x 20 cent stamp gives you 2.4. Since there are three times less, there would be 4 x 5 cent Stamp. There are 2 less 8 cent stamp so there is 2 x 8 cent stamp.

12 = 2.4
4 = 0.2
2 = 0.16
--------------
2.76 ( 4 Is Your Answer)

Answer 6

You just need to set up the equations and solve.

Let F be the number of 5 cent stamps
Let E be the number of 8 cent stamps
Let T be the number of 20 cent stamps

T = 3F
E = F - 2
5F + 8E + 20T = 276

There you go -- three equations and three unknowns. You should be able to take it from there.

Answer 7

x relates to the 5 cent stamps
y relates to the 8 cent stamps
z relates to the 20 cent stamps

3x = z [3x-z=0]
x-2 = y [x-y=2]
.05x+.08y+.20z=2.76 multiply this by 100 so you don't have to deal with decimals, therefore getting:
5x+8y+20z=276

using elimination methods,
5x+8y+20z=276
3x-z=0 multiply by 20 = 60x-20z=0

so,
65x+8y=276
then, use the other equation, x-y=2, multiply by 8

65x+8y=276
8x-8y=16
: 73x = 292
x = 4
so you have four 4 cent stamps.

then plug 4 back into the other equations to find your y and z if necessary.

Answer 8

12*.20=2.40
4*.05=.20
2*.08=.16
Total=2.76
12 twenty cents, 4 five cents, and 2 eight cents

Answer 9

x = 5 cents
y =8 cents
z = 20 cents

3z = x
y-2=x
x+y+z=2.76

now you have three equations and three unknowns,
you have to do the rest.