How would i round the answers, the significant figures?

if it says 908 ounces there is 3 sig figs therefore you will want 3 sig figs in your rounding which would give you 25.7 kilograms... and this would be true for 6 weeks as well... there is only 1 sig fig therefore you would use 1000 hours. remember 0 do not count as sig figs unless they are after a decimal. So 1000 is only 1 sig fig.