Size of brick with Mortar = 20 cm × 10 cm × 10 cm
No. of bricks required per 1 m3 brickwork = 1 / (0.2 × 0.1 × 0.1) = 500 nos.
No. of bricks for 10 m3 brickwork = 500 × 10 = 5000 nos.
Size of brick without Mortar = 19 cm × 9 cm × 9 cm
Actual volume of 5000 bricks = 5000 × (0.19 × 0.09 × 0.09) = 5000 × 0.001539 = 7.695 m3
approx 7.7 m3