Question

For 3kwh load find the bill at the rate of RS 3 per unit.

Answer 1

1 Kwh = 1 unit 
so 
for 3 Kwh at rs 3 
it will 3 x 3 = 9 rupees 

Answer 2

$1km = 1unit then 3perunit = 3km 3 \times 3 = 9$