Question

How many numbers below 90 and other than unity exist,such that the hcf of that number and 90 is unity

Answer 1

Answer:

23 numbers are below 90 such that the hcf of that number and 90 is unity

Step-by-step explanation:

90 = 2 * 3 * 3 * 5

So Any number other than which is having Any of these factors  will have hcf of 1 with 90

Such numbers will be

7  ,   11    ,   13   , 17    , 19    , 23    ,  29   , 31   , 37    , 41   , 43  , 47   , 49 , 53

59 , 61   , 67  ,  71  , 73   , 77 ,  79  , 83  ,  89  

so 23 Such Numbers

23 numbers are below 90 such that the hcf of that number and 90 is unity