Answer and Explanation:
The journal entries are shown below:
On Jan 31 
Treasury stock (50,000 shares × $51) $2,550,000 
 To cash $2,550,000 
(being the reacquired shares are recorded)
For recording this we debited the treasury stock as it increased the blaance of treasury stock and credited the cash as it reduced the assets 
On June 14 
Cash (24,000 shares × $60 ) $1,440,000 
 To Treasury stock (24,000 shares × $51) $1,224,000 
 To Paid-In Capital from Sale of Treasury Stock $216,000 
(Being the reacquired shares are sold)
For recording this we debited the cash as it increased the assets and credited the treasury stock and paid -in the capital as it reduced the treasury stock balance and increased the stockholder equity 
On Nov 23 
Cash (18,000 shares × $56 ) $1,008,000 
 To Treasury stock (18,000 shares × $51) $918,000 
 To Paid-In Capital from Sale of Treasury Stock $90,000
(Being the reacquired shares are sold)
For recording this we debited the cash as it increased the assets and credited the treasury stock and paid -in the capital as it reduced the treasury stock balance and increased the stockholder equity