It is 1600 seconds. You divided 31,360 by 9.8 and you get 3200. Then divide 3200 by 2 and you get the answer 1600 seconds.
3200
33% of 3200= 33% * 3200= 0.33 * 3200= 1,056
5% of 3200 = 5% * 3200 = 0.05 * 3200 = 160
3200 = 3200/1 in fraction
3200
5% of 3200 = 3200*5/100 = 160
3200-1800 = 1400
2.5% of 3,200= 2.5% * 3200= 0.025 * 3200= 80
3200² = 10,240,000
It is: MMMCC = 3200
18% of 3,200= 18% * 3200= 0.18 * 3200= 576