Because he’s taxed by his home planet, Mork pays a tax rate of 45% on his income, while Mindy pays a rate of only 15% on hers. If Mindy earned 4 times as much as Mork did, what was their combined tax rate?  Choose the correct choice from the following options
A) 19%
B) 21%
C) 23%
D) 25%
E) 27%
Let x be Mork's income, then Mindy's income is 4x.   The total tax paid is 0.45x + 0.6x = 1.05x   1.05x / 5x  0.45  + 0.6= 
<gadget id="calculator"> 0.45  + 0.6</gadget>
<output>1.05</output>
1.05x   1.05x / 5x = 0.21   The answer is 21%. 1.05  / 5= 
<gadget id="calculator"> 1.05  / 5</gadget>
<output>0.21</output>
0.21   The answer is 21%.
<result>B</result>
Because he’s taxed by his home planet, Mork pays a tax rate of 45% on his income, while Mindy pays a rate of only 15% on hers. If Mindy earned 4 times as much as Mork did, what was their combined tax rate?