Adam spends $24.70 on a sticker, a marble and a bead. The marble costs $1.20 more than the bead. The sticker costs 1/3 as much as the marble. What is the cost of 3 stickers, 2 marbles and 4 beads?

2 answers

s+m+b = 24.70
m = b + 1.20
s = 1/3 m
Now solve for s,m,b and you want 3s+2m+4b

Post your work if you get stuck
let x = cost of a bead
x + 1.2 = cost of a marble
1/3 (x + 1.2) = cost of a sticker
[x + x + 1.2 + x/3 + 1.2/3 = 24.7]3
3x + 3x + 3.6 + x + 1.2 = 74.1
7x = 74.1 - 3.6 - 1.2
7x = 69.3
x = 69.3/7
x = 9.9
x + 1.2 = 11.1
(x + 1.2)/3 = 3.7
Cost of 3 stickers, 2 marbles and 4 beads
= 3(3.7) + 2(11.1) + 4(9.9)
= 11.1 + 22.2 + 39.6
= $72.9