Adam pays $10.60 for 3 marbles and 2 beads.
A marble costs $2.70 more than 1 bead.
What is the cost of 4 marbles and 3 beads?
Choose the cheaper item to be 1 u.
1 marble costs $2.70 more than 1 bead.
The cheaper item is the bead.

Cost of the bead = 1 u
Cost of the marble = 1 u + 2.70

Cost of 3 marbles = 3 x (1 u + 2.70) = 3 u + 8.10
Cost of 2 beads = 2 u

Total cost of 3 marbles and 2 beads
= 3 u + 8.10 + 2 u
= 3 u + 2 u + 8.10
= 5 u + 8.10

5 u + 8.10 = 10.60
5 u = 10.60 - 8.10
5 u = 2.50

1 u = 2.50 ÷ 5 = 0.50

Cost of 4 marbles and 3 beads
= 4 x (1 u + 2.70) + 3 u
= 4 u + 10.80 + 3 u
= 4 u + 3 u + 10.80
= 7 u + 10.80
= 7 x 0.50 + 10.80
= 3.50 + 10.80
= $14.30

Answer(s): $14.30