Question 995334: How many integers greater than 1 million and less than 9 million are perfect square?
A. 1999
B. 2000
C. 2001
D. 3000
Answer by jim_thompson5910(35256) (Show Source):
You can put this solution on YOUR website! sqrt(1,000,000) = 1,000
sqrt(9,000,000) = 3,000
If you square a whole number between 1,000 and 3,000 (exclusive) you'll get a result that is a whole number between 1 million and 9 million (exclusive).
There are 3000-1000+1 = 2000+1 = 2001 whole numbers that span from 1,000 to 3,000. You can count them yourself, but the handy shortcut formula is where m is the starting whole number and n is the ending whole number (and you count by ones).
If we exclude the endpoints 1 million and 9 million, then we subtract off 2 to get the final answer of A. 1999
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