Numbered poles are placed alongside a highway with an equal distance between...

[randy.lahey]

[FONT=&quot]Numbered poles are placed alongside a highway with an equal distance between each two adjacent poles. To get from pole number 1 to pole number 21 takes 38 minutes. How much time, in minutes, will pass going from pole number 21 to pole number 51?[/FONT]

 

[HallsofIvy]

Let the distance between poles, in feet, be "x". The distance from pole 1 to pole 27 is (27- 1)x= 26x. Since that was done in 38 min the speed is 26x/38 feet per minute. The distance from pole 21 to pole 51 is (51- 21)x= 30x. At the same 26x/38 feet per minute, the time taken will be (30x)/(26x/38)= (30x)(38/26x)= 1140/26 minutes.