Find the x, the unit price
3x = 1.45
3x /3 = 1.45 / 3
x = 0.483 cost per pack.
Find x, the number of packs bought
21.75 = 0.483x
0.483x = 21.75
0.483x / 0.483 = 21.75 / 0.483
x = 45 packs bought
Find total cost of 60 packs
x = 0.483(60)
x = 28.98 is the total cost. $30 is more than enough to pay for 60 packs.