(N/A) To draw the frequency polygon without a histogram,we first calculate the class marks (mid-points) for each interval.
| Class interval $(km/h)$ | Class marks | Frequency |
| $30-40$ | $35$ | $3$ |
| $40-50$ | $45$ | $6$ |
| $50-60$ | $55$ | $25$ |
| $60-70$ | $65$ | $65$ |
| $70-80$ | $75$ | $50$ |
| $80-90$ | $85$ | $28$ |
| $90-100$ | $95$ | $14$ |
$1$. Plot the points $(35, 3), (45, 6), (55, 25), (65, 65), (75, 50), (85, 28),$ and $(95, 14)$ on a graph paper.
$2$. To close the polygon,include two additional class intervals with zero frequency: $20-30$ (mid-point $25$) and $100-110$ (mid-point $105$).
$3$. Join the points $(25, 0), (35, 3), (45, 6), (55, 25), (65, 65), (75, 50), (85, 28), (95, 14),$ and $(105, 0)$ with line segments to obtain the frequency polygon.