Liang Xiao information consultation

Set x hours to catch up.

Xiaoming leads15×1=15km.

So when catching up, Liang Xiao traveled more than15km.

So 30x- 15x= 15.

15x= 15

x= 1

That is to say, when catching up, Liang Xiao traveled 30× 1=30 kilometers.

But it's only 28 kilometers.

So Xiao Liang can't catch up with Xiaoming.