Maria bought 10 notebooks and 5 pens costing 2 dollars each.How much did Maria pay?  Choose the correct choice:
A) $ 10  B) $ 20  C) $ 30  D) $ 40  E) $ 50

Rationale: 2 × ( 10 + 5 ) = 2 × 10 + 2 × 5 = 20 + 10 = 30 dollars correct answer is c ) $ 30
Answer: C