Finding an unknown in a formula

The heights of some students are grouped as follows:

- $140 < x \le 145$: 2 students
- $145 < x \le 150$: $p$ students
- $150 < x \le 155$: 14 students
- $155 < x \le 160$: 10 students
- $160 < x \le 165$: 4 students

Given that the estimated mean height is 153 cm, find the value of $p$. (Use class midpoints.)