他的原计划是每小时走：s/t计划改变后是每小时走：s/(t-1)所以每小时多走：s/(t-1)-s/t=s/t(t-1)
s/(t-1)-s/t=s/(t(t-1))每小时应多走s/(t(t-1))km
s/(t-1)-s/t=s/t(t-1)
答案是：(S/T-1)-(S/T)=S/T(T-1)
s/t(t-1)
