Question 1079608: find the greatest four digit number which on being divided by 6,12,18,24,and 30 leaves remainder 4 in each case
Answer by Edwin McCravy(20054) (Show Source):
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The LCM of 6,12,18,24,30 is 360, so the only positive integers that
will leave remainder 4 when divided by all of those is 4 more than
a multiple of 360. Such a number would be of the form 360n+4.
1000 ≦ 360n+4 ≦ 9999
Subtract 4 from all three sides:
996 ≦ 360n ≦ 9995
Divide all three sides by 360:
2.7666... ≦ n ≦ 27.763888...
Since n is an integer:
3 ≦ n ≦ 27
So the smallest such 4 digit number is when n=3, 360*3+4 = 1084.
And the greatest such 4 digit number is when n=27, 360*27+4 = 9724.
Answer: 9724.
Edwin
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