Ratio problem, please help.....:) thanks

[billyr]

The number of stamps that kaye and alberto had were 5:3, after kaye gave alberto 10 of her stamps, the ratio were 7:5. Kaye had how many stamps more than alberto?

a)10
b)20
c)40
d)50
e)60




The right answer is c, but i don't know why i got e

this is my solution:

Kaye stamps=x alberto stamps =y

first equation x/y=5/3

second equation (x-10)/(y+10)=7/5


5y=3x----->3x-5y=0 from first equation


7y+70=5x-50---->5x-7y=120 from second eqaution



solving it i got x= 150 and y=90, thus the difference is 60 but why the answer is 40.......thanks

[bravotalks]

I don't see anything wrong in your approach.

X is 150 and Y is 90, and you have deduced X - Y
But the question (probably) asks for (X-10) - (Y+10) i.e, after 10 stamps are given.

So after 10 stamps are given kaye has 140, alberto has 100, diff is 40.

[sureshbala]

Folk, we have to give the present difference between their stamps

Presently K has 140 and has 100. So the difference is 40

[billyr]

I don't see anything wrong in your approach.

X is 150 and Y is 90, and you have deduced X - Y
But the question (probably) asks for (X-10) - (Y+10) i.e, after 10 stamps are given.

So after 10 stamps are given kaye has 140, alberto has 100, diff is 40.

thanks, that make it clear