Canada had silver dimes and quarters up till 1968 but we had them up till 1965, why did they have silver dimes and quarters longer than us?
It's almost like they were another country with another system of laws governing how they ran their own country...
They didn't have them longer than us. The U.S. first began minting Dimes and Quarters in 1796. Canada did not have a Dime until 1858 and the Quarter until 1870. Two different countries, two different monetary systems. Canada is governed by the United Kingdom.
Check the silver fineness. Your answer is there. Also, Canada in 1968 had some made in [gasp!] Philadelphia.
I read and understood the question correctly. I just added some more information in my usual sarcastic manner The last two sentences answers the question.
Kurt gave you the answer. The Canadian coins were of lower silver fineness than ours so it took longer before the metal value exceeded the face value. Then Canada tried to buy some time by reducing the fineness even more rather than giving up silver completely. That gave them another year or so, but they finally had to surrender and give up silver in the circulation coins too.