I believe it is number iii #3
3 times the product of 5 and b is reduced by 2
3*(5*b)-2
15b-2
To figure this out, you need to multiply all the dimensions together. 100x30=. 3,000cm and 3,000x12= 36,000 cubic centimeters. So now you can divide the 36,000 by 1000 to get the amount of liters the entire tank can hold. 36,000/1000= 36 liters. And because you want to know how much half of the tank is, you divide 36 by 2 and get 18 liters
