Sam had a total of 80 foreign stamps amd local stamps combined. after giving away 1/3 of his foreign stamos and 10 local stamps he had an equal number left. how many stamps did they have in the beginning

Call x the number of foreign stamps and y the number of local stamps. We write equations: x+y=80 2x/3=y-10 Adding ten to the last equation, we have: y=2x/3+10 Substituting this for y in the first equation, we have: 5x/3+10=80 Subtracting ten, we have: 5x/3=70 Multiplying by 3/5, we see that x=42, and y=80-42=38, so there are 42 foreign stamps and 38 local stamps.