As shown in the graph, the case is the price increase in the inferior good, I have failed to understand why when the price increase in the inferior good, the income effect is positive and offset the substitution effect, please explain the question I have asked .

FIGURE 4.8 Y($/wk) Income and Substitution Effects for an Inferior 34 Good B' By contrast to the case of a normal good, the income 24 effect acts to offset the substitution effect for C 18 an inferior good. B1 12 A 6 lo Bo Hamburger (lb/wk) 0 8 9 12 15 1 18 24 Total 17 effect Income effect Substitution effect