Henrikh lives x blocks from his office. It takes him 1 minute per block to walk to
work and 20 seconds per block to ride his bicycle to work. If it takes him exactly
7 minutes more to walk to work than to ride his bicycle, then x equals
Choices:
A) 4
B) 7
C) 10.5
D) 15
E) 20
The best way would be...   Per km, he takes 40 secs extra if he walks   So he will take 7 mins or 7*60 secs in 7*60/40= 
<gadget id="calculator">7*60/40</gadget>
<output>21/2 = around 10.5</output>
10.5 km   ANSWER:10.5
<result>C</result>
Henrikh lives x blocks from his office. It takes him 1 minute per block to walk to
work and 20 seconds per block to ride his bicycle to work. If it takes him exactly
7 minutes more to walk to work than to ride his bicycle, then x equals