Quantitative Aptitude :: Numbers - Discussion

2880 number

given options   1 ,5,6,2

the last 2-digits of number 2880 is  80

80/2 =40 x

80/1 =80 x

80/6 =not possible

80/5 =16

  so, Among all options 5  is smallest number.

Solution: Do option verification

2880 on dividing by 5 gives 576 which is 24^2

By trial and error method, we get
2880/3 = 960 is not a perfect square
2880/4 = 720 is not a perfect square
2880/5 = 576 which is perfect square of 24
Hence, 5 is the least number by which 2880 must be divided in order to make it into a perfect square.

2880/2=1440, which is also a perfect square, then why only 5?

2^6*3^2*5