Because he’s taxed by his home planet, Mork pays a tax rate of 40% on his income, while Mindy pays a rate of only 30% on hers. If Mindy earned 5 times as much as Mork did, what was their combined tax rate?  Choose the correct choice from the following answers:
A) 32.5 %
B) 34 %
C) 35 %
D) 31.67 %
E) 37.5 %

Rationale: "say morks income is - 100 so tax paid will be 40 say mindys income is 5 * 100 = 500 so tax paid is 30 % * 500 = 150 total tax paid = 40 + 150 = 190 . combined tax % will be 190 / 100 + 500 = 31.67 %"
Answer: D