alice and bob drive at constant speeds toward each other on a highway. alice drives at a constant speed of 30 km per hour. at a certain time they pass by each other, and then keep driving away from each other, maintaining their constant speeds. if alice is 100 km away from bob at 7 am, and also 100 km away from bob at 11 am, then how fast is bob driving ( in kilometers per hour )? Choose the correct choice from the following answers.
A) 20  B) 24  C) 28  D) 32  E) 36
<gadget id="calculator">100 + 100</gadget>
<output>200</output>

<gadget id="calculator">11 - 7</gadget>
<output>4</output>

<gadget id="calculator">200 / 4</gadget>
<output>50</output>

<gadget id="calculator">50 - 30</gadget>
<output>20</output>

<result>A</result>
alice and bob drive at constant speeds toward each other on a highway. alice drives at a constant speed of 30 km per hour. at a certain time they pass by each other, and then keep driving away from each other, maintaining their constant speeds. if alice is 100 km away from bob at 7 am, and also 100 km away from bob at 11 am, then how fast is bob driving ( in kilometers per hour )?
subtract(divide(add(100, 100), subtract(11, 7)), 30)
alice and bob complete 200 km / 4 hours = 50 km / hour bob ' s speed is 50 - 30 = 20 km / hour the answer is a .