To isolate the income effect, compare the consumption bundle at point C, 6 Jell-O cubes and 28 grapes, to the consumption bundle at point B, 9 Jell-O cubes and 42 grapes. Based on the income effect alone, the monkey will consume 3 more Jell-O cubes and 14 more grapes. Combining the income effect and the substitution effect together yields the total effect of 5 more Jell-O cubes and 6 more grapes