Question

The greatest number of 4 digits which is exactly divisible by 40,48 and 60​

Answer 1

9,840 is the greatest number like that.
Here is a list of all numbers like that, starting from 0. You'll see that the highest one is 9840.
0
240
480
720
960
1200
1440
1680
1920
2160
2400
2640
2880
3120
3360
3600
3840
4080
4320
4560
4800
5040
5280
5520
5760
6000
6240
6480
6720
6960
7200
7440
7680
7920
8160
8400
8640
8880
9120
9360
9600
9840

Answer 2

9840

Explanation:

LCM of 40,48 and 60 is 240.

The factors of 40=2 * 2 * 2 * 5

48=2 * 2 * 2 * 2 * 3

The LCM of 40 and 48 is = 2 * 2 * 2 * 5 * 2 * 3 = 240

60=2 * 2 * 3 * 5

240=2 * 2 * 2 * 5 * 2 * 3

LCM of 240 and 60 is=2 * 2 * 5 * 3 * 2 * 2=240

Therefore LCM of 40, 48 and 60 is=240

If you look at the multiples of 240 ...

240*10=2400

240*40=9600

240*50=12000

You will find that 240*41=9840 is the largest four digit multiple of 240( 240*42 is a five digit number)

Therefore, 9840 is the largest four digit number which is exactly divisible by 40, 48 and 60.