There ia truck which should reach some place at 11'o clock , if it travels with 30 mph it reaches i hour before, if it travles with 20 mph it reaches 1 hour late. what is the distance it must be travlled and what is the speed it must maintain to rech at exact time?  Answers
A) 22 kmph  B) 24 kmph  C) 26 kmph  D) 28 kmph  E) 20 kmph
let S T D are the speed time and distance   S=D/T   according to question,   30=D/(T-1)..........1   and   20=D/(T+1)..........2   dividing equation 1 by 2 we get T=5 hours   now,   for distance put value of T in equ 1   then D=120 m   now,   for exact time s=d/t   =120/5= 
<gadget id="calculator">120/5</gadget>
<output>24</output>
24 kmph   ANSWER:24 kmph
<result>B</result>
There ia truck which should reach some place at 11'o clock , if it travels with 30 mph it reaches i hour before, if it travles with 20 mph it reaches 1 hour late. what is the distance it must be travlled and what is the speed it must maintain to rech at exact time?