Swifts are the fastest birds flying long distances. A swift can fly 85 kilometers in 0.5 hours, which is 10.5 kilometers faster than a carrier pigeon per hour. How many miles per hour do pigeons fly?
雨燕是长距离飞行最快的鸟．一只雨燕0.5小时可飞行85千米，比一只信鸽每小时飞行的速度还要快10.5千米．信鸽每小时飞行多少千米？
<gadget id="calculator">85 / 0.5</gadget>
<output>170</output>

<gadget id="calculator">170 - 10.5</gadget>
<output>159.5</output>

<result>159.5</result>