Step-by-step explanation:
12/3.48= cost of 1 book
cost of 20 books = 12/3.48×20 =68.95
Answer:
28
3(x + 7) = 57 |÷3
x + 7 = 57/3
x + 7 = 19 |-7
x = 19 - 7
x = 12
