Question

(4. Determine the greatest 5-digit number which is
exactly divisible by each of 8, 15 and 21. step by step solution
​

Answer 1

Answer:

99960

Step-by-step explanation:

By investigating the prime factorizations of 8 (2x2x2), 15 (3x5), and 21 (3x7), you can determine that their Least Common Multiple is 2x2x2x3x5x7 which is 840. The greatest 5 digit number is 99999. When you divide that by 840, you get 119 and a remainder. So your answer is 840x119 = 99960.

Answer 2

Tᴏ Fɪɴᴅ :- The Greatest 5 digit number exactly divisible by 8 , 15, and 21 ?

Sᴏʟᴜᴛɪᴏɴ :-

The greatest 5-digit number is 99999.

Now, Find the LCM of 8 , 15, and 21.

3 | 8 15 21

2 | 8 5 7

2 | 4 5 7

2 | 2 5 7

5 | 1 5 7

7 | 1 1 7

| 1 1 1

LCM :- 3 * 2 * 2 * 2 * 5 * 7 = 840.

Now, Divide 99999 by 840 so that we get the remainder...

→ 99999 = 840 * 119 + 39

Remainder we get is 39.

Now, Subtract the remainder from 99999.

→ 99999 - 39 = 99960 (Ans.)

Hence, The required number is 99960 which is exactly divisible by by 8 , 15 and 21.