Question

From the numbers 2, 3, 4, 5, 6, 7, 8, 9 how many pairs of co-primes can be formed?
(a) 19
(b) 18
(c) 20
(d) 21
pls give explanation​

Answer 1

Answer:

7

Step-by-step explanation:

7 was paired with 2, 3, 4, 5 and 6 earlier each, so these are deducted. Hence the set becomes {8, 9}. Thus 2 pairs can be formed - (7, 8) and (7, 9).