D) A water tank holds 256 gallons, but is leaking at a rate of 3 gallons each week. After how many weeks will the tank contain only 193 gallons of water?

21 Weeks

Step-by-step explanation:

First you need to find the amount of water lost:

256-193 = 63

Then divide by 3

63/3 = 21

1gm = 1000mg so 0.1gm = 1000mg

first, convert the weight to kg

160lb * 1kg/2.2lb = 72.7kg

next, the dose

72.7kg * 100mg/kg = 7270mg