1. If the product of these integers is to be 1, then all of them must be either 1 or -1.
2. Since the product is positive (+1), it must be that there are an *even* number of negative ones (-1), if any.
3. If the sum were 0 it would mean that the number of +1's must equal the number of -1's. So that means there would have to be exactly 22/2=11 of each.
4. But if there were 11 of each, that means the number of -1's would be *odd* and there's no way the product could be +1 (as stated in 2 above).
Hence, the sum is never 0, if the product of 22 integers is equal +1.
Answer:
her brother is 15 years old
Step-by-step explanation:
let 'b' = her brother's age
Harriet is 3 years old but Harriet is also '1/3b - 2'
3 = 1/3b - 2
5 = 1/3b
b = 5(3) or 15
2t+3n=9 2(2)+3n=9
+5t-3n=5 (the 3n cancel out) 4+3n=9
7t=14 3n=5
t=2 n=5/3 or 1.67
