Ali, Ben, Charles and Dave had some stickers. Ali and Ben had a total of 17 stickers. Ben and Charles had 16 stickers in all. The product of the number of Ali's stickers and the number of Charles' stickers was 30. Given that Ali had \( {2 \over 3}{}{}\)as many stickers as Dave, how many stickers did the children have altogether?
+118667 A+B=17 (1)
B+C=16 (2)
(1)-(2)
A+B-B-C = 17-16
A - C = 1
so
A=1+C
Now
A*C = 30 so
(1+C)*C = 30
c^2+C-30=0
(C-5)(C+6)=0
C = 5 or -6
but C is positive so C=5
so
A=1+C = 6
I think you can take it from there to find B and D
Note that there is one piece of info in the question that I have not used yet. 
