A car's value, in thousands of pounds, is V=A+Be−t/6V=A+Be^{-t/6}V=A+Be−t/6. The graph passes through (0,18)(0,18)(0,18) and has horizontal asymptote V=4V=4V=4. Find A A\,A and BBB, then find V V\,V when t=6t=6t=6.