A bicycle tyre contains air with volume 3.5 × 10−3 m3, pressure 320 kPa and temperature 14 ℃. A bicycle pump contains air with volume 1.6 × 10−4 m3, pressure 100 kPa and temperature 18 ℃.
The tyre is pumped up until the air inside has volume
3.6 × 10−3 m3, temperature 24 ℃, and a pressure of at least 350 kPa.

Calculate the number of complete strokes of the pump needed to reach at least 350 kPa.