Convert the mixed fraction 33 1/3 into an improper fraction first, and then multiply the 150 by the numerator of the fraction.
Let's look at 33 1/3. Ignore the 1/3; would you agree that 33 is the same as 33/1? Because anything with a denominator of 1 means you're dividing the numerator by 1, which will give you the same number in return. To make the 33/1 have a denominator of 3, we need to multiply the denominator by 3. But when we do that, we have to multiply the numerator by 3 as well in order to not change the value of the fraction. So:
33/1 = (33 * 3)/(1 * 3) = 99/3
99/3 and 1/3 = 99/3 + 1/3 = 100/3
Now that we converted 33 1/3 into 100/3, we just need to multiply the 150 by 100 in the numerator, which will give 15000/3, which simplifies to 5,000 as your answer.