Q: The number of stamps that Kaye and Alberto had were in the ratio 5:3, respectively. After Kaye gave Alberto 10 of her stamps, the ratio of the number Kaye had to the number Alberto had was 7:5. As a result of this gift, Kaye had how many more stamps than Alberto?
a)20
b)30
c)40
d)60
e)90
OA: C
My solution (which is wrong) -->
> K:A = 5x/3x
>(5x-10)/(3x+10) = 7/5
>25x-50 = 21x+70
>25x-21x = 70+50 --> 4x = 120
>x = 30
Kaye had 7x = 210 stamps
Alberto had 5x = 150 stamps
Answer (wrong): 210 - 150 = 60
Where did I go wrong?
a)20
b)30
c)40
d)60
e)90
OA: C
My solution (which is wrong) -->
> K:A = 5x/3x
>(5x-10)/(3x+10) = 7/5
>25x-50 = 21x+70
>25x-21x = 70+50 --> 4x = 120
>x = 30
Kaye had 7x = 210 stamps
Alberto had 5x = 150 stamps
Answer (wrong): 210 - 150 = 60
Where did I go wrong?
