+218 Five different positive integers added two at a time give the following sums: 16, 20, 22, 23, 25, 28, 29, 30, 34, and 37.
Find the product of the five integers.
Thanks.
+31 Let the numbers be a < b < c < d < e
Then the smallest two, a and b, must have sum 16,
a + b = 16
and the largest two, d and e, must have sum 37,
d + e = 37.
Then the middle number c is equal to 66 - (a+b) - (d+e) = 66 - 16 - 37 = 13.
OK. So, the two smallest numbers a and b give the sum of 16, and the third number is 13.
It means that the next sum, 20 (see the condition) is a+c.
It can not be nothing else.
If a + c = 20 and c = 13, then a = 20 - 13 = 7.
It implies b = 16-7 = 9.
So, the first three numbers are a = 7, b = 9 and c = 13.
OK. Now we can make the similar analysis from the other end.
So, the two largest numbers d and e give the sum of 37, and the third number in the descending order is 13.
It means that the next from the largest sum, 34 is e+c.
It can not be nothing else.
If e + c = 34 and c = 13, then e = 34 - 13 = 21.
It implies d = 37-21 = 16.
Thus the numbers are 7, 9, 13, 16 and 21.
Their product is 275184.
hope this helps!
+218 Not to be rude, but thanks for the solution off of Algebra.com.
I need to know where we got 66 from!
+31 wait! I'm a doofus, add all the given numbers and divide by 4 ( 4 because you are taking into account the numbers excluding the one you are looking at)
THAT would get you 66
+218 Oh thanks for the answer! I wasn't expecting a reply! Thanks! I get it now!
+218 Wait, why are we taking into account all the numbers except for the one we are looking at? Can you tell me?
