Q: You need to read the given passage and construct a question about the information present in the passage. The question should be answerable from the passage. Most importantly, only those questions are allowed whose answers cannot be determined from a single sentence. Do not generate questions that require only a single sentence to answer. Instead, try to combine two sentences and create a question from that combination. Do not create open-ended questions, i.e., the answers to them cannot be found precisely from the information provided in the passage.
Paragraph- Sent 1: (CNN) -- Britain's Chris Froome won the 17th stage of the Tour de France on Wednesday to strengthen his grip on the yellow jersey.
Sent 2: Froome completed Wednesday's 32-kilometer time trial in 51 minutes 33 seconds, nine seconds ahead of Spain's Alberto Contador with his compatriot Joaquim Rodriguez Oliver finishing a further second behind in third.
Sent 3: "I couldn't believe it when I got over the line and saw I had the fastest time," Froome said after his third stage win of this year's tour.
Sent 4: "I went into today thinking I was going to try and limit my losses, thinking about the days to come now.
Sent 5: So to go through the finish line with the fastest time, I really didn't see that coming."Sent 6: On mountainous terrain along a frequently twisting route most of the riders opted for their traditional road bikes over the more aerodynamic machines used in time trials.
Sent 7: But Froome opted to use both on the stage, switching to a time trial model for the final 12-kilometer descent.
Sent 8: The swap proved decisive as the Briton clawed back a 20-second advantage Contador had built up earlier in the stage.
Sent 9: The Spaniard now moves up to second overall, four minutes 34 seconds behind Froome with just four stages remaining.
Sent 10: Contador's Saxo-Tinkoff teammate Roman Kreuziger is now third and trails Froome by four minutes and 51 seconds.
Sent 11: Thursday sees the riders tackle the gruelling 172.5-kilometer 18th stage which concludes with a double ascent of Alpe d'Huez over the last 60 kilometers.
A:
How long did Fromme  bike on the 17th stage before the final descent?