Help on a math problem?

Question

I posted this question already but I forgot the total amount. >_>

well, here it is again.

A postal clerk sold 50 postage stamps for $15.84. Some were 37-cent stamps, and the rest were 23-cent stamps. Find the number of 37-cent stamps that were sold.

Answer 1

ok. lets say x represents the 37 cent stamps and y represents the 23 cent stamps

x + y = 50 ... right? ok good

now in reference to the cost

.37x + .23y = 15.84 ... right? ok good

if you subtract .37x from both sides to get y by itself, you get

.23y = 15.84 - .37x

then divide both sides by .23 to get y completely alone so that

y = 68.869565 - 1.608696x ... following?

now since x + y = 50, if you subtract x from both sides you get

y = 50 - x

you now have 2 equations for y. if y = a and y = b, that means a = b

so .....

50 - x = 68.869565 - 1.608696x

if you add 1.608696x to both sides you get

50 + .608696x = 68.869565

now subtract 50 from both sides to get

.608696x = 18.869565

no divide both sides by .608696 to get x by itself

you get x = 31

if you plug that into x + y = 50

you get y = 19

which means you have 31 of the 37c stamps and 19 of the 23c stamps.

if you plug it in .... 19(.23) + 31(.37) you get $15.84

Answer 2

x = number of 37-cent stamps

y = number of 23-cent stamps

x + y = 50  ==> x = 50 - y

37x + 23y = amount sold in cents

37(50 - y) + 23y = amount sold in cents

(37)(50) - 37y + 23y = 1584

1850 - 14y = 1584

-14y = (1584 - 1850)

y = (1584 - 1850) / -14 = (-266) / -14 = 19

x = 50 - y = 50 - 19 = 31

There were 31 stamps sold of 37-cent value.

Answer 3

No. of 37-cent stamps sold (x):

37x + 23(50 - x) = 100(15.84)

37x + 1,150 - 23x = 1,584

14x = 434

x = 31

Answer: 31 pieces of 37-cent postage stamps were sold.

Proof (Total sales amounted to $15.84):

= $0.37(31) + $0.23(50 - 31)

= $11.47 + $0.23(19)

= $11.47 + $4.37

= $15.84

Answer 4

I think it's 31 stamps out of 37 cent value... but really i don't know cuz ya didn't say the total amount