I need some algebra help please!!!!!?

Question

ok im trying to help my little cousin on her algebra hw, but i got stuck on this one, can any of you please help us??!!But just give us the equations to solve it and we'll be ok...THANKS!! ok heres the problem:
A postal clerk sold some fifteen-cent stamps and some twenty-five cent stamps. Altogether, 10 stamps were sold for a total cost of $1.70. How many of each type of stamp were sold?

ok maybe we need the answer too, and all the steps of the problem because we're still confused.....thsnks lol.

ok, we STILL dont get how to distribute the 2 equations and get the answers...sorry, we're kinda slow...lol

Answer 1

15x+25y=170

Answer 2

Let the number of 15 cent stamps be x, and 10 cent stamps y.

x + y = 10

15x + 25y = 170

From the first equation, if you take x away from both sides you get
y = 10 - x

So replace y by 10 - x in the second equation and get

15x + 25(10 - x) = 170
[Another answerer came up with this equation as the starting point]

Remove parentheses:
15x + 250 - 25x = 170

250 - 10x = 170

You might be able to see from this immediately that
10x = 80, since 80 is what you have to take away from 250 to get 170; otherwise use formal processes:

Add 10x to both sides:
250 = 170 + 10x

Take 170 from both sides:
80 = 10x

Hence x = 8
Since x + y = 10, we now get
y = 2

So there were 8 fifteen cent stamps (cost $1.20) and 2 twenty-five cent stamps (cost $0.50)

Answer 3

For the purposes of the answer - a is the number of fifteen-cent stamps, and b is the number of 25-cent stamps:

a + b = 10
(a x .15) + (b x .25) = 1.70

Thus:
a = 10 - b; replace a with the expression 10 - b in the second equation:

((10 - b) x .15) + (b x .25) = 1.70

(1.5 - .15b) + (.25b) = 1.70
1.5 + .10b = 1.70
.10b = 1.70 - 1.5
.10b = .20
b = 2

Substitute 2 for b in the first equation:

a + 2 = 10
a = 8

Thus, you have 8 stamps at 15 cents, plus 2 stamps at 25 cents, totaling $1.70

Answer 4

Let x be the number of 15-cent stamps sold, and let y be the number of 25-cent stamps.

Since 10 stamps were sold, x+y=10.
Since $1.70 was spent, 15x+25y=170.

Multiply the first equation by 15 and subtract it from the second equation, and you'll be able to find x and y.


I am sure this might be the answer,just check it out...

Answer 5

Let x be the number of 15-cent stamps sold, and let y be the number of 25-cent stamps.

Since 10 stamps were sold, x+y=10.
Since $1.70 was spent, 15x+25y=170.

Multiply the first equation by 15 and subtract it from the second equation, and you'll be able to find x and y.

Answer 6

8 15 cent stamps, and 2 25 cent stamps.

the problem is solved by
15x + 25y = 1.70
x + y = 10

Answer 7

2 25 cent stamps and 8 15 cent stamps
.15(10-s)+.25(s)=1.70

Answer 8

Two 25 cent stamps and eight 15 cent stamps

Answer 9

Let the number of 0.15c stamps sold be x
And the number of 0.25c stamps sold be y

Since a total of 10 stamps were sold, we have that

x + y = 10 ...... (1)

Since the total cost is $1.70, we have

0.15x + 0.25y = 1.70 ....(2)

From (1), we make x the subject of the formula, we have

x = 10 - y ...... (3)

Substitute this value in (2), we have

0.15 (10 - y) + 0.25y = 1.70
1.5 - 0.15y + 0.25y = 1.70
1.5 +0.10y = 1.70 (because -0.15y + 0.25y = 0.25y - 0.15y)
0.10y = 1.70 - 1.5
0.10y = 0.2
y = 0.2/0.10
y = 2

Substitute this value of y in (3)

x = 10 - y
x = 10 - 2
x = 8

This means that 8 pieces of 0.15c and 2 pieces of 0.25c stamps were sold.


Check using (2)

0.15x + 0.25y = 1.70
0.15X8 + 0.25X2 = 1.70
1.2 + 0.5 = 1.7
1.7 = 1.7!

Answer 10

You need to define the variables. x=15 cent stamps y=25 cent stamps

then you set up two equations
x+y=10
.15x+.10y=1.70

then use either substitution or elimination

Answer 11

15x+25y=170
x+y=10
(x is the number of 15 c stamps and y is the number of 25c stamps)