one is even, the other is odd if you want the sum to be prime (that is, odd)
Only B works for that
Marcy found two numbers that satisfy the following rules:
● Has one prime number
● Has one composite number
● The sum of the numbers is prime
Problem
Which two numbers could be the numbers that Marcy found?
A
23 and 27
B
11 and 20
C
8 and 16
D
13 and 15
4 answers
B
Because:
In answer A
23 and 27
Both numbers are prime.
In answer C
8 and 16
Both numbers are composite numbers.
In answer D
13 and 15
13 is prime 15 is composite, but their sum 13 + 15 = 28 is not prime.
So in answer B:
11 is prime, 20 is composte.
Their sum 11 + 20 = 31 is prime.
Because:
In answer A
23 and 27
Both numbers are prime.
In answer C
8 and 16
Both numbers are composite numbers.
In answer D
13 and 15
13 is prime 15 is composite, but their sum 13 + 15 = 28 is not prime.
So in answer B:
11 is prime, 20 is composte.
Their sum 11 + 20 = 31 is prime.
My typo.
In answer A
23 and 27
23 is prime 27 is composite, but their sum 23 + 27 = 40 is not prime.
In answer A
23 and 27
23 is prime 27 is composite, but their sum 23 + 27 = 40 is not prime.
A
0 answers