Question

Example 3. Show that one and only one out of
n, n +4, n +8, n + 12 and n + 16 is divisible by 5,
where n is any positive integer. NCERT Exemplar​

Answer 1

Answer:

for any no. to be divisible by 5...it has to be a multiple of 5...

from the given numbers

n, n+4, n+8, n+12, n+16

put all the natural numbers from 1 to infinity

for n = 1 ,

(n+4 = 5) which is the only number out of the given 5 that is divisible by 5...

similarly we can check for n = 2,3,4,5....and so on.

We will get only one number divisible by 5 .