Martin went on an eight-hour business trip. During the first half of the trip, he traveled at a speed of 70 kilometers per hour and during the second half at a speed of 85 kilometers per hour. How many kilometers did he travel during the journey?
Half of the trip lasts for 8 * 0.5 = 
<gadget id="calculator">8*0.5</gadget>
<output>4</output>
4 hours.
During the first half, Martin did 4 * 70 = 
<gadget id="calculator">4*70</gadget>
<output>280</output>
280 kilometers.
And during the second half 4 * 85 = 
<gadget id="calculator">4*85</gadget>
<output>340</output>
340 kilometers.
In total Martin traveled 280 + 340 = 
<gadget id="calculator">280+340</gadget>
<output>620</output>
620 kilometers during his business trip.

<result>620</result>