express 36,40,54 and 60 as sum of two prime numbers
Answers
1) 36 / 2 = 18
18 - 1 = 17
18 + 1 = 19
17 and 19
2) 40 / 2 = 20
20 - 1 = 19
20 + 1 = 21
21 and 19
3) 54 / 2 = 27
27 - 20 = 7
27 + 20 = 47
47 and 7
4) 60 / 2 = 30
30 - 1 = 29
30 + 1 = 31
31 and 29
Hope this helps :)
1) 36
36= 18 + 18 (WRITE IT AS A SUM OF ITS HALF)
36= (18+1) + (18-1)
36= 19+ 17
2) 40
40 = 20 + 20
40 = (20-1) + (20+1)
40 = 19 + 21
But 21 is not a prime number since it has factors like 3 and 7
Hence we take 3 instead of 1 ( Note 2 cannot be taken since the number becomes an even composite number)
⇒40 = 20 + 20
⇒40 = (20-3) + (20-3)
⇒40 = 17 + 23
Both 17 and 23 are prime numbers : )
3) 54
54 = 27 + 27
=( 27 -1) + (27+1)
= 26 + 28 Not possible since they are not prime numbers
Now try out with numbers like 2,3,4
On trying with 4,
54 = 27 + 27
= ( 27 -4) + (27+4)
54 = 23 + 31
4) 60
60 = 30+30
60 = (30-1) + (30+1)
60 = 29 + 31
Note : You may get different answers since there are many prime numbers : )
Thank U : )