Last year a bicycle cost $160 and a cycling helmet $40. This year the cost of the bicycle increased by $5\%$, and the cost of the helmet increased by $10\%$. The percent increase in the combined cost of the bicycle and the helmet is:
$\text{(A) } 6\%\quad \text{(B) } 7\%\quad \text{(C) } 7.5\%\quad \text{(D) } 8\%\quad \text{(E) } 15\%$
Since the bicycle originally cost $160, the new cost will be 160 * 5% = 160 * 1/20 = 8, and 160 + 8 = 168. The new cost of the helmet will be 40 * 10% = 40 * 1/10 = 4, and 40 + 4 = 44. 160 + 40 = 200, and 168 + 44 = 212, so the total percent increase is 12/200 = 6%, or A.