AMC 8 2007 Problem 5

Chandler wants to buy a $500$ dollar mountain bike. For his birthday, his grandparents send him $50$ dollars, his aunt sends him $35$ dollars and his cousin gives him $15$ dollars. He earns $16$ dollars per week for his paper route. He will use all of his birthday money and all of the money he earns from his paper route. In how many weeks will he be able to buy the mountain bike? $\mathrm{(A)}\ 24 \mathrm{(B)}\ 25 \mathrm{(C)}\ 26 \mathrm{(D)}\ 27 \mathrm{(E)}\ 28$