Quiz

hi and thank you Bohumil

i am trying some day on create Grade according my need via your link...but i can't replicate my need.can you help me little more?only simple example please give me.

my need: 

i have quiz A with 10 question:

quiz A = q1+q2+q3+q4+q5+q6+q7+q8+q9+q10

i need 5 different grade

GradeX= q1+q3

GradeY=q2+q4

Gradez=q3+q6

.

.

.

can you say me how to give result of GradeX and GradeY and...?

thank you...