interesting question, as it seems indeterminable from the data given. You know that the speed of person one, or S1 times four hours will yield the distance and that S2 times two hours will yield the same distance, so S1 = 1/2 of S2. The only speeds that are possible then for S1, out of the choices are 25,26, 27, 28, 29 and 30, since doubling these speeds would yield a speed for S2 that is within guidelines (50-60). Problem is, these six number pairs all yield a workable, but different solution ranging in distances from 100 up to 120. so my answer would be d= between 100 and 120.

shibal wrote:Two people walked the same distance, one person's speed is between 25 and 45,and if he used 4 hours, the speed of another people is between 45 and 60,and if he used 2 hours, how long is the distance?

don't have the OA sorry

range for person1- 25*4=100 and 45*4=180. so 100<d<180
range for person 2-4582=90 and 60*2=120, so 90<d<120
common range is 100<d<120. that is the answer

S1, S2 Speed of person 1 and 2 resp.
t1, T2 Time taken by person 1 and 2 resp ie 4 and 2 hrs
D Distance

Since, D= ST
=> S1T1 = S2T2
=> S1/S2 = 1/2

From the range of S1 and S2 we can derive
S1,S2 to be
(25, 50) (26,52)....(30,60)

So distance would be
Min D=S2T = 50*2 =100
Max D= 60*2 = 120

so, 100<= D <=120