Statement 1: If two numbers are co-primes, at least one of them must be prime.
Statement 2: If a number exactly divides the sum of two numbers, it must exactly divide the two numbers separately.
Statement 3: If a number exactly divides two numbers, then it must also divide the sum of both numbers.
False, False, True
Take an example and visualize-
i) C0-prime do not have any factors in common other than 1; Consider the numbers 9 and 4 ; They are co-prime but both of them are not prime.Hence the 1st statement is false.
ii) Now, 12 + 16 = 28; but 28 does not divide 12 and 16.Hence the second statement is false.
iii) Consider the numbers 4, 12 and 16
12 and 16 are both divisible by 4 and also sum of 12 + 16 = 28 is divisible by 4; Hence the third statement is true
4 also divides 12+16 = 28