Since all five classes are equal width (10 marks each), the histogram's bars are drawn directly to the class boundaries with height equal to frequency.

Since the class widths are all equal (10 marks each), the histogram's rectangle heights are simply the class frequencies themselves, drawn directly against the class boundaries.

Step 1 — Verify the total. $4+10+16+12+8$: $4+10=14$, $14+16=30$, $30+12=42$, $42+8=50$ — matches the 50 students stated in the question, confirming no class was mistranscribed.

Step 2 — Draw the histogram. Mark class boundaries $0,10,20,30,40,50$ on the X-axis and frequency on the Y-axis. Draw five rectangles, each of width 10, with heights $4, 10, 16, 12, 8$ respectively, touching each other (no gaps, since the classes are continuous).

Leaving gaps between the rectangles (treating this like a bar diagram) is the single most common histogram mistake — since marks are continuous data, the bars must touch. Using the class limits …