Question

Let p & q be the number of natural numbers which are less than or equal 20 and are prime & composite
respectively, then 20 - p -q is equal to
(A) 1
(B) O
(D) 3
​

Answer 1

Answer:

3 is correct for many numbers

Step-by-step explanation:

Let p & q be the number of natural numbers which are less than or equal 20 and are prime & composite

So p: prime numbers less than or equal to 20

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

q: composite numbers less than or equal to 20

q: 4,6,8,9,10,12,14,15,16,18,20

So 20-p-q=20-2-4=14

20-p-q= 20-7-10= 3

20-p-q= 20-11-6=3

20-p-q= 20-13-4=3

20-p-q= 20-2-15=3

So in many options 3 comes up.

So option 3 is correct.

But many others answers also comes up with the given range,it may you don't put range correctly.