Write five pairs of prime numbers less than 20 whose sum is divisible by 5.
Answer
386.1k+ views
Hint: Prime numbers are natural numbers which have only two factors 1 and the number itself.
Set of prime numbers less than 20 are:
$\left( {2,3,5,7,11,13,17,19} \right)$
According to the given problem,
Pair of prime numbers less than 20, whose sum is divisible by 5 are:
$
\left( i \right)\left( {2,3} \right)\left[ {\because 2 + 3 = 5} \right] \\
\left( {ii} \right)\left( {3,7} \right)\left[ {\because 3 + 7 = 10} \right] \\
\left( {iii} \right)\left( {2,13} \right)\left[ {\because 2 + 13 = 15} \right] \\
\left( {iv} \right)\left( {7,13} \right)\left[ {\because 7 + 13 = 20} \right] \\
\left( v \right)\left( {13,17} \right)\left[ {\because 13 + 17 = 30} \right] \\
$
Since the sum of every set is divisible by 5.
Hence the pairs are $\left( {2,3} \right)\left( {3,7} \right)\left( {2,13} \right)\left( {7,13} \right)\left( {13,17} \right)$
Note:Any natural number which has only two factors i.e. 1 and the number itself called a prime number. In the above question we just did a combination of all prime numbers and tried for the sum of all the sets.
Set of prime numbers less than 20 are:
$\left( {2,3,5,7,11,13,17,19} \right)$
According to the given problem,
Pair of prime numbers less than 20, whose sum is divisible by 5 are:
$
\left( i \right)\left( {2,3} \right)\left[ {\because 2 + 3 = 5} \right] \\
\left( {ii} \right)\left( {3,7} \right)\left[ {\because 3 + 7 = 10} \right] \\
\left( {iii} \right)\left( {2,13} \right)\left[ {\because 2 + 13 = 15} \right] \\
\left( {iv} \right)\left( {7,13} \right)\left[ {\because 7 + 13 = 20} \right] \\
\left( v \right)\left( {13,17} \right)\left[ {\because 13 + 17 = 30} \right] \\
$
Since the sum of every set is divisible by 5.
Hence the pairs are $\left( {2,3} \right)\left( {3,7} \right)\left( {2,13} \right)\left( {7,13} \right)\left( {13,17} \right)$
Note:Any natural number which has only two factors i.e. 1 and the number itself called a prime number. In the above question we just did a combination of all prime numbers and tried for the sum of all the sets.
Recently Updated Pages
Define absolute refractive index of a medium

Find out what do the algal bloom and redtides sign class 10 biology CBSE

Prove that the function fleft x right xn is continuous class 12 maths CBSE

Find the values of other five trigonometric functions class 10 maths CBSE

Find the values of other five trigonometric ratios class 10 maths CBSE

Find the values of other five trigonometric functions class 10 maths CBSE

Trending doubts
Which country launched the first satellite in space class 11 physics CBSE

Difference Between Plant Cell and Animal Cell

Fill the blanks with the suitable prepositions 1 The class 9 english CBSE

Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE

What is the past tense of read class 10 english CBSE

Change the following sentences into negative and interrogative class 10 english CBSE

What is pollution? How many types of pollution? Define it

Give 10 examples for herbs , shrubs , climbers , creepers

Write a letter to the principal requesting him to grant class 10 english CBSE
