part 2 question,plz somebody explain

[amrita1]

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a 40 lb. child requires mutiple dental procedures under local anaesthesia.The max. number of catridges of lidocaine with 1:100,000 epinephrine that may be safely administered at one time is
1. 1
2.3
3.5
4.8
5.10

 

[ExxonMobil]

Maximum dosage to administer to a child is 4.4mg/kg = 2mg/lb
Since the child is 40lbs, 40lbs x 2mg/lb = 80mg of maximum amount of lido. Next, we know that each 2% cartridge contain 36mg of lido. We take 80mg/36mg/cartridge = 2.22 cartridges. So in term of cartridges, we shouldn't use more than 2. The answer is 2 and I don't see it in the choices.