Question

1. Find the ratio of the number of prime numbers to the number of composite numbers between the numbers 1 and 20​

Answer 1

Find the first 10 primes, and store them in p:

]p=.p:i.10

2 3 5 7 11 13 17 19 23 29

Count the primes in the range 2 - 25:

+/p e.~ 2 to 25

9

Count the non-primes in the range 2–25:

+/-.p e.~ 2 to 25

15

So the ratio is 9/15 or 3/5.

Answer 2

Answer:

4:5 or 4/5 will be the answer.