I have a question and solution as well ,but I don't understand it: If r distinct objects are to be distributed into n distinct boxes each box can hold any number of objects and the ordering of objects in each box matters,
Then we can put first object in n ways. For placing the $2^{\text nd}$ objects we presume that we have divided the box containing $1^{\text st}$ object into 2 parts (one part left to the object and the other right to the object). So $2^{\text nd}$ object can be placed in n+1 ways. Continuing like this ,we can place $i^{\text th}$ object in $n+i-1$ ways.
total no. of ways for placing r objects are : $n(n+1)\ldots(n+r-1)$.I can't understand why is it $n+1$ ways for $2^{\text nd}$ object?