Math Question.. Pls Help?

Question

Mandy has a total of 560 Malaysian and Singapore stamps at first. After giving away 5/7 of her Malaysian stamps and 1/3 of her Singapore stamps, the no. of Singapore stamps was 3 times the no. of Malaysian stamps. How many Malaysian stamps did Mandy have at first? I need workings pls...

Thanks a million

Answer 1

Let m be the number of Malaysian stamps.
The the number of Singapore stamps is 560-m............(1)
After giving away 1/3 of her Singapore stamps, she has 2/3 of them left. That is 2(560-m)/3.
After giving away 5/7 of her Malaysian stamps, she has 2/7 of them left. That is 2m/7.
Therefore 2(560-m)/3 = 3*2m/7 = 6m/7.
Multiply both sides of the equation by 21:
14(560-m) = 18m
14*560 = 32m
m = 14*560/32 = 245.
She therefore has 245 Malaysian stamps, and from (1) she has 560-245 = 315 Singapore stamps.

Answer 2

let m be # of malaysian stamps
let s be # of singapore stamps

"Mandy has a total of 560 Malaysian and Singapore stamps at first"
m + s = 560

"After giving away 5/7 of her Malaysian stamps and 1/3 of her Singapore stamps, the no. of Singapore stamps was 3 times the no. of Malaysian stamps. "
if she gave away 5/7 of her malaysian stamps, she has 2/7 left. if she gave away 1/3 of her singapore stamps, she has 2/3 left
so
"the no. of Singapore stamps was 3 times the no. of Malaysian stamps."
(2/3)s = 3(2/7)m
2s/3 = 6m/7
let;s cross multiply and then solve for s
2s * 7 = 6m * 3
14s = 18m
divide both sides by 14
s = 18m/14
s = 9m/7

let's sub that in the first equation
m + s = 560
m + (9m/7) = 560
7m/7 + 9m/7 = 560
16m/7 = 560
cross multiply
16m = 3920
divide both sides by 16
m = 3920/16
m = 245

answer: 245 malaysian stamps

Answer 3

Let
M = number of malaysian stamps, and S=number of singaporean

you know that

M + S = 560

after she gave away a bunch,

(S-1/3S)=3(M-5/7M)
2/3S = 6/7M
14S = 18M

substituting from the first equation,

14(560-M) = 18M
14*560 - 14M = 18M
14*560 = 32M
14*140 = 8M
14*35 = 2M
M = 7*35 = 245
thus S = 560 - M = 315.

Answer 4

no.of malaysian = M
no.of singapore = S
M + S = 560
2/3S = (3*2/7)M -> 1/3 S = 3/7 M -> S = 9/7 M
M + 9/7 M =560 -> M = 245

Answer 5

let no.of Malaysian stamps = M
let no. of Singapore stamps = S
so S + M = 560

she gives away 5/7M and 1/3S
so she has now 2/7M + 2/3S

also 2/3S = 3*(2/7M)
so S = 9/7M

so M + 9/7M = 560
solving M = 1280 stamps
no of malaysian stamps = 1280
is that ok?