Answer :
2800 + 1.18x = y
x = monthly sales
y = monthly income
y needs to be at least 6400 so that means;
2800 + 1.18x ≥ 6400
1.18x ≥ 6400 - 2800
x ≥ (6400 -2800) / 1.18
x ≥ 3050
So she needs to earn at least 3050, which means ≥ 3050
x = monthly sales
y = monthly income
y needs to be at least 6400 so that means;
2800 + 1.18x ≥ 6400
1.18x ≥ 6400 - 2800
x ≥ (6400 -2800) / 1.18
x ≥ 3050
So she needs to earn at least 3050, which means ≥ 3050