Question

colored copies cost .10 cents white copies cost .5cents sandy make 400 copies , some of which were colored and the rest white. her total was $22.50. how many colored copies and how many white did she made?

Answer 1

let colored copies be represented by C
let white copies be represented by W
.10C+.5W=22.50
C+W=400

Answer 2

sine C+W=400, then W=400-C.
so .10C+.5(400-C)=22.50
.10C+200-.5C=22.50
-.4C+200=22.50
-.4C=22.50-200=-177.5
C=-177.5/(-.4)=443.75
But thats impossible since Sandy only made 400 copies

Answer 3

did you mean white copies cost .5 cents or .05 cents?

Answer 4

.05 cents

Answer 5

ok so we have .10C+.05W=22.50
C+W=400 implies W=400-C
so .10C+.05(400-C)=22.50
.10C+20-.05C=22.50
.05C+20=22.50
.05C=22.50-20=2.5
C=2.5/(.05)=50
since W=400-C, then W=400-50=350

Answer 6

i did it like this..c+w=400
.10c+5w=22.50
multiply#1 equation by .10
.10c-10w=17.50
add#3 equation and #2
400c=17.50
c=228
w+228=400

Answer 7

but it doesn't match with the price:(

Answer 8

ok did you understand how I got W=350 and C=50?

Answer 9

no how???

Answer 10

C+W=400
I solved for W and got
W=400-C then I plugged this into the other equation

Answer 11

ok now i got it thank you you save me from failing algebra :)

Answer 12

lol k

Answer 13

i got another ???

Answer 14

an airplane flew for 5 hours with a tail wind of 25km/h. The return flight against the same wind took 5.5 hours. find the speed of the plane in still air