Which of the following numbers is not divisible only by prime numbers, itself and 1? Ext A 21 B 77 C 110 D 221 E 65
Mathematics · Middle School · Tue Nov 03 2020
Answered on
Answer is D = 221
Because as we know 21 is divisible by 3 , 77 is divisible by 7 , 110 is divisible by 11 , 65 is divisible by 5 but only 221 is one number doesn't divisible by any of prime number
Explanation : In the mathematics we have 5 prime numbers they are - 2 , 3 , 5 , 7 and 11
So , simple we divide 221 with all the prime number and we get results are :
221 / 2 = 110.5
221 / 3 = 73.67
221 / 5 = 44.2
221 / 7 = 31.58
221 / 11 = 20.010
So , 221 is the number that doesn't divisible by any prime number and the simple reason is that the number 1 that will come in this number. Because 1 is never divisible by any number expect itself 1.