Question

for how many integers between 20 and 30,is it true that 5/a ,7/a and 8/a are all in lowest terms​

Answer 1

Answer:

Step-by-step explanation:

we are looking for natural numbers a where 20 <= a <= 30 such that a is coprime with 5 , 7 and 8 , that is,

hcf(a , 5 , 7 , 8) = 1. thus

a € {3 , 9 , 11 , 13 , 17 , 19}