Answer:
He can buy 4 model cars
Step-by-step explanation:
∵ His total money = the cost of books + the cost of model cars
∵ He buys 6 books and the price of each book is $2
∵ The cost of each model car is $7 , let the number of model cars is c
∵ He has $40
∴ 6 × 2 + 7 × c = 40
∴12 + 7c = 40
∴ 7c = 40 - 12 = 28
∴ c = 28/7 = 4
∴ He can buy 4 model cars
