Question

Chisaka has less than 145kg of food remaining in her spaceship. She needs a constant amount of food each day that she spacewalks, and a constant amount of food each day that she doesn't spacewalk. Let S represents the number of days Chisaka spacewalks and N represents the number of days she doesn't spacewalk without running out of food. 2.2S+1.3N < 145 According to the inequality, how much food does Chisaka need for each day that she does and doesn't spacewalk?

Answer 1

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 $S=0$ in our inequality to find how long her food will last if she does not spacewalks:
$2.22S+1.3N\ \textless \ 145$
$2.22(0)+1.3N\ \textless \ 145$
$1.3N\ \textless \ 145$

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.