Question

Write three pairs of prime numbers less than 20 whose sum is divisible by 5​

Answer 1

Answer:

The pairs of numbers are (7, 13) and (13, 17) and (19, 11)

Solution:

Given that we have to write three pairs of prime numbers less than 20 whose sum is divisible by 5

Let us first list the prime numbers less than 20

A prime number is a whole number greater than 1 whose only factors are 1 and itself

Prime numbers less than 20 are:

2, 3, 5, 7, 11, 13, 17, 19

We have to find pairs of prime numbers in above list whose sum is divisible by 5

Number that are divisible by 5 must end in 5 or 0

7 + 13 = 20 = divisible by 5

13 + 17 = 20 = divisible by 5

19 + 11 = 30 = divisible by 5

Thus the pairs of numbers are (7, 13) and (13, 17) and (19, 11)

Answer 2

Answer:

The prime numbers are 5, 10, 15, and 20.