a biker notices a certain number(2 digits number) on the milestone before starting the journey. After riding for an hour he notices a milestone with reversed digits of the previous number. Now after riding for another hour he notices that the number on a new milestone had same digits as the first one (in the same order) but with a "0" between the 2 digits. If the rider maintains a constant speed throughout, Calculate his speed.	Pick
A) 40 B) 45 C) 50 D) 55 E) 60
let first two digit number is xy = 10x + y   after one hour, the number is reversed yx = 10y + x   after another one hour, it x0y = 100x + y.   now xy &lt; yx &lt; x0y   so, (10y + x) - (10x + y) = (100x + y) - (10y + x)   or, 9(y - x) = 9(11x - y)   or, 12x = 2y   the above equation will be true only if x = 1 and y = 6.   hence, his speed is 45   ANSWER:45
<result>B</result>
a biker notices a certain number(2 digits number) on the milestone before starting the journey. After riding for an hour he notices a milestone with reversed digits of the previous number. Now after riding for another hour he notices that the number on a new milestone had same digits as the first one (in the same order) but with a "0" between the 2 digits. If the rider maintains a constant speed throughout, Calculate his speed.