Alocal charity held a crafts fair selling donated, handmade items. total proceeds from the sale were 1380. a total of 72 items were sold, some at 15 each and the rest at 25 each

X = 25 dollar items and y = 15 dollar items

x + y = 72x = 72 - y
25x + 15y = 1380

25(72 - y) + 15y = 1380
1800 - 25y + 15y = 1380
-25y + 15y = 1380 - 1800
-10y = - 420
y = -420/-10
y = 42

x + y = 72
x + 42 = 72
x = 72 - 42
x = 30

so they sold 30 twenty five dollar items (x) and 42 fifteen dollar items (y)