Question

You have 105 cowry shells. If a dozen eggs cost 10 cowry shells, how many eggs can you purchase?

Answer 1

`126` eggs

Explanation:

As a dozen i.e. `12` eggs cost `10` cowry shells,

each cowry shell can buy `12/10` eggs

and `105` cowry shells can buy `12/10xx105` eggs

= `12/(cancel10^2)xxcancel105^21` eggs `-`dividing by `5`

= `(cancel12^6)/(cancel2^1)xx21` eggs `-`dividing by `2`

= `6xx21=126` eggs

Answer 2

If we can only buy eggs by the dozen, then we end up with `120" eggs" and 5 " cowry shells"`

Explanation:

An alternate way of looking at this problem is to ask if we can only buy eggs by the dozen. If so, then we can buy 10 sets of a dozen eggs each and have 5 cowry shells left over. This gives:

`10xx12=120" eggs" and 5 " cowry shells"`