The pupils are 9 equal units. Two units failed, so the other 7 units passed = 28.

Pupils444444444passed 28 = 7 units

Plain numbers are given; italic underlined numbers are worked out.

  1. Passed = 7 units → 28
  2. 1 unit → 28 ÷ 7 = 4
  3. Failed = 2 units → 2 × 4 = 8

The number who failed is 8.

Check: 8 failed + 28 passed = 36; 2⁄9 of 36 = 8. ✓