Adam pays $10.70 for 3 marbles and 2 beads.
A marble costs $1.40 more than 1 bead.
What is the cost of 2 marbles and 3 beads?
Choose the cheaper item to be 1 u.
1 marble costs $1.40 more than 1 bead.
The cheaper item is the bead.

Cost of the bead = 1 u
Cost of the marble = 1 u + 1.40

Cost of 3 marbles = 3 x (1 u + 1.40) = 3 u + 4.20
Cost of 2 beads = 2 u

Total cost of 3 marbles and 2 beads
= 3 u + 4.20 + 2 u
= 3 u + 2 u + 4.20
= 5 u + 4.20

5 u + 4.20 = 10.70
5 u = 10.70 - 4.20
5 u = 6.50

1 u = 6.50 ÷ 5 = 1.30

Cost of 2 marbles and 3 beads
= 2 x (1 u + 1.40) + 3 u
= 2 u + 2.80 + 3 u
= 2 u + 3 u + 2.80
= 5 u + 2.80
= 5 x 1.30 + 2.80
= 6.50 + 2.80
= $9.30

Answer(s): $9.30