Please help my Maths problem....I just can't figure it out

Question

Amanda,Brinda and Dayang share 9z packets of beads. Amanda gets z packets more than Brinda, Dayang gets 6 packets more than Brinda,

a) How many packets does Brinda get in terms of z?

b) If Amanda gets 3 packets more than Brinda, how many packets does Brinda get?

Answer 1

Use letters A, B and D to represent the amounts each gets. From the info A=B+z; D=B+6; A+B+D=9z. Substitute for A and B in the last equation: B+z+B+B+6=9z, 3B=8z-6. Part b says that z=3, because A=B+z=B+3, so Brinda gets (8*3-6)/3=6 packets of beads. Now check it out: A=6+3=9; D=6+6=12; B=6, so A+B+D=27=9*3. Right!