Value of g=9.8ms^-2 in si if unit of length is doubled and unit of time is halved then find numerical value of?

If using halfseconds (hs) as unit of time and doublemeters (dm) as unit of length then the value of g would be 9.8 (0.5 dm)*(2 hs)^-2 = 9.8 * 0.5 * 2^-2 dm hs^-2 = 9.8 / 8 dm hs^-2 = 1.2 dm hs^-2