Answer
The Miracle Chip Light must have a maximum of 6.67 calories or a maximum of 0.75 grams of fat.
Work Step by Step
If the light product must contain at least one-third as many calories as the regular one and the regular product contains 20 calories, that means that it must contain $\frac{20}{3}$ calories or less. In an inequality, this is represented as $x\leq\frac{20}{3}$
Similarly, with the fat, it must contain at least one-half less than the regular one. So, if the regular one has 1.5 grams, the light one must have a maximum of 0.75 grams or $x\leq0.75$