Let's name:
[tex]E:\text{Stamps from Egypt} \\ \\ P:\text{Stamps from Peru} \\ \\ N:\text{Stamps from Nigeria}[/tex]
1. He has 4 more stamps from Egipto than from Peru:
[tex]E=P+4 \ \ \ \cdots eq1[/tex]
2. He has 3 fewer stamps from Nigeria than from Egipto.
[tex]N=E-3 \ \ \ \cdots eq2[/tex]
3. He has 27 stamps from Nigeria:
[tex]N=27 \ \ \ \cdots eq3[/tex]
Substituting eq3 into eq2:
[tex]27=E-3 \\ \\ E=27+3 \\ \\ E=30[/tex]
Substituting E into eq1:
[tex]30=P+4 \\ \\ P=30-4 \\ \\ P=26[/tex]
So he has:
