given that A,B,C and D are whole numbers such that A+B=8, B+C=11,B+D=13 and C+D=14, find the values of A,B,C and D.

A+B=8, B+C=11,B+D=13 and C+D=14 

(B+C)+(B+D)=11+13 
2B+(C+D)=24
2B+14=24
2B=10
B=5 

A=3
C=6
D=8 

:)