A children's liquid medicine contains 100 mg of the active ingredient in 5 mL. If a child should receive 150 mg of the active ingredient, how many milliliters of the medicine should the child be given? For the purposes of this question, assume that these numbers are exact. The package states that one teaspoon (tsp) is approximately equal to 5 mL. Calculate the number of teaspoons that the child should receive. Use the given approximation as your conversion factor.