Question

A clown at a birthday party has brought along a helium cylinder, with which he intends to fill balloons. When full, each balloon contains 0.00280 m3 of helium at an absolute pressure of 1.20 x 105 Pa. The cylinder contains helium at an absolute pressure of 2.90 x 107 Pa and has a volume of 0.00280 m3. The temperature of the helium in the tank and in the balloons is the same and remains constant. What is the maximum number of people who will get a balloon?

I keep getting 242, which is incorrect. My lecturer said something about not being able to use all the gas in the tank due to pressure, which is where I am getting confused.