+0  
 
0
117
1
avatar

Find the smallest positive multiple of 21 that has no digit smaller than \(5\).

 Jan 29, 2022
 #1
avatar+2444 
0

Let's count the multiples of 21 that are less than 100: 21, 42, 63, 84

 

 The next possible range is \(>550\), (because anything less always has a digit less than 5 in the hundreds or tens place):

 

The multiples are: 567, 588, 609...

 

We can see that the smallest number with no digit less than 5 that is divisible by 21 is \(\color {red}567\)

 Jan 29, 2022

31 Online Users

avatar