We need to use consistent units throughout. The 2 g of drug is equivalent ot 2000 mg.

**Rough estimate:** We expect the dosages to be around 700 mg and 1300 mg, based on similar thinking to Example 1 above.

Let the amount the adult gets be *d* mg.

The child will get *d −* 660.

Together, the two dosages must be: *d* + (*d* − 660) = 2000

That is 2*d* − 660 = 2000

2

d= 2660

d= 1330

And *d* − 660 = 1330 − 660 = 670

So the adult gets 1330 mg and the child gets 670 mg.

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