text: t  the tens digit\nu  the units digit\n\n 6(t+u)=10t+u\n5u=4t\n5/4u = t   Now since t an u must be whole number digits,\nu must be a multiple 4, like 4 or 8.\nIf u=4 then t=5/4(4)=5 and the number would be 54.\nLet's check\n 6(5+4)=6(9)=54    OK\n\nLet's try u=8\n(5/4)(8)= 10 which is supposed to  be t but 10 is not a digit\n\n\nSo 54 is the only answer