Beth walked 3 blocks in 15 minutes. based on this rate, determine if this statement is true or false

So I looked up the max size for the width of a block in most American cities, and it said one block can be 660 feet.
Under these circumstances, she's walking 1980 feet.
It takes about 19.5 minutes to walk a mile if you're walking at an average pace of 3.1 miles per hour.
1980 feet is 0.375 miles
19.5 times 0.375 is 7.3125 minutes average.
And that's IF she's walking on three 660 foot wide blocks.

I'd say false, because it would take less time than that