Find the number of 4-digit numbers that contain at least three even digits.

4625 numbers

Step-by-step explanation:

To solve this problem we can separate it in different cases, and then we sum the amount of numbers of each case to find our final result.

The first case is: all four numbers are even.

We have 5 even digits, and the first digit of the 4-digit number can't be zero, so for the first digit we have 4 possible values, and for the other 3 digits we have 5 possible values, then the amount of numbers with this condition is:

The second case is the number having three even digits and one odd digit, and the first digit is the odd digit.

In this case, the first digit has 9 possible values (all digits but zero) and the other 3 digits have 5 possible values (even digits):

The third case is the number having three even digits and one odd digit, and the first digit is not the odd digit.

In this case, the first digit has 4 possible values, the odd digit has 10 possible values and the other two digits have 5 possible values. The odd digit can be the second, the third or the fourth digit, so we multiply our result by 3 (because we will find the same result if we choose the odd digit to be the second, third or fourth):

So the final result is the sum of these cases:

d. millimeters per hour.

step-by-step explanation:

we are given that,

carlo used a rain gauge to measure the amount of water his lawn is receiving from the sprinklers.

since, according to the options, we see that,

water cannot be measured by 'miles per hour', 'meters per second' and 'grams per seconds'.

we get that, the water can be measured by 'millimeters per hour'.

hence, the appropriate rate for describing the amount of water is 'millimeters per hour'.