Question

a blackboard is 35 cm long by 25 cm what will be the cost of 20 at a rate of 40 m at a rate of per square centimetre​

Answer 1

$25 \times 35 \\ \times 20 \\ \times 40 \\ = 7lakh \times the \: unit$

I don't know what's the unit here.... इस it m?