If Chisaka does not space walks, the days she spend spacewalking are equal to zero. Since S represents the number of days Chisaka spacewalks, we just need to replace [tex]S=0[/tex] in our inequality to find how long her food will last if she does not spacewalks:
[tex]2.22S+1.3N\ \textless \ 145[/tex]
[tex]2.22(0)+1.3N\ \textless \ 145[/tex]
[tex]1.3N\ \textless \ 145[/tex]
From this calculation we can infer that the coefficient of N, 1.3, is the amount of food she needs per day if she doesn't spacewalks. Similarly the coefficient of S, 2.2, is the amount of food she need per day if she spacewalks.
We can conclude that Chisaka will need 1.3 kg of food if she doesn't spacewalks, and 2.2 kg of food if she spacewalks.
