
By: Strawberry (offline) Thursday, February 23 2012 @ 01:10 PM CST (Read 885 times)



Strawberry 
Yesterday, the ratio of the number of stamps Ali had to that of Zainal's was 9:11. This morning, Zainal gave Ali 255 stamps. Now the ratio of the number of Ali's stamps to Zainal's stamp is 3:2. How many more stamps has Ali than Zainal now?

Regular Member
Registered: 01/31/09 Posts: 83





By: pkrdd (offline) Thursday, February 23 2012 @ 10:40 PM CST



pkrdd 
Hi,
For this problem, take note that the total number of stamps altogether is constant. so you have to apply constant total method which is  to equate units to same before and after
Before Ali : Zainal = 9: 11 ie total 20 units
After Ali : Zainal = 3:2 (multiply by 4 to make total units as 20)
= 12: 8
Zainal gave 255 which is 11u  8u = 3u
u = 255/3 = 85
Now Ali has 4units more than Zainal (12 8) = 4 * 85 = 340 stamps more
Hope this helps.

Junior
Registered: 01/11/10 Posts: 16



