Question

what is the greatest 4 digit number which is divisible by 20,30,50

Answer 1

Answer:

The prime factorizations of 30 and 40 are 30 = 2 x 3 x 5 and 40 = 2 x 2 x 2 x 5, so their least common multiple is 2 x 2 x 2 x 3 x 5 = 120. Thus, any number evenly divisible by both 30 and 40 must be evenly divisible by 120. Since 10,000/120 gives a quotient between 83 and 84, the number we want must be 83 x 120, or 9,960. As a check, 9,960/30 = 332, and 9,960/40 = 249, exactly divisible!

Answer 2

Answer:

9960,9990 is the answer