SOLUTION: The product of three consecutive positive integers is 21 times their sum. Find the sum of the three integers. (a) 24 (b) 27 (c) 30 (d) 33 (e) None of the above

Algebra ->  Problems-with-consecutive-odd-even-integers -> SOLUTION: The product of three consecutive positive integers is 21 times their sum. Find the sum of the three integers. (a) 24 (b) 27 (c) 30 (d) 33 (e) None of the above       Log On


   

Question 289007: The product of three consecutive positive integers is 21 times their sum. Find the sum of the three integers.
(a) 24 (b) 27 (c) 30 (d) 33 (e) None of the above


Found 2 solutions by nyc_function, Fombitz:
Answer by nyc_function(2741) About Me  (Show Source):
You can put this solution on YOUR website!
Here's what to do:
1-E-mail your question to me at nycfunction@yahoo.com
2-Include your fax number (most people have a fax number at home these days)
3-I will then fax the entire question and fully explained answer.
NYC Math Tutor

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
N - First integer
N+1 - Second consecutive integer
N+2 - Third consecutive integer
N%2A%28N%2B1%29%2A%28N%2B2%29=21%2A%28N%2BN%2B1%2BN%2B2%29
N%2A%28N%2B1%29%2A%28N%2B2%29=21%2A%283N%2B3%29
N%2Across%28%28N%2B1%29%29%2A%28N%2B2%29=63%2Across%28%28N%2B1%29%29
N%2A%28N%2B2%29=63
N%5E2%2B2N=63
N%5E2%2B2N-63=0
+%28N-7%29%28N%2B9%29=0+
Two solutions:
+N-7=0
+N=7
.
.
.
+N%2B9=0
+N=-9%0D%0A
The problem only asks for "three consecutive positive integers" so N=-9 is not a solution.
The three integers are 7,8, and 9.