Answer:
to be divisible by 10 the number must end in a zero. That is the last of the 4 digits used and one of the numbers provided.
There are now 5 numbers left (3, 5, 7, 8 & 9) since we used the 0 already, and only 3 more digits required to make up our 4 digit number.
The number of ways you can pick these numbers is 5P3 = 5 * 4 * 3 = 60 ways.
In other words you can pick any of the 5 remaining numbers for the first digit, any of the remaining 4 numbers for the second digit and any of the remaining 3 numbers for the third digit, with the last digit 0.
If you can pick the same number as many times as you like then to make a 4 digit number the first digit must be non zero so you have 5 numbers to choose from. The second and third digits can be any of the numbers, so you have 6 numbers to pick from. The last number must be zero. This means there are 5 * 6 * 6 * 1 = 180 ways
