6000 - 1800 = 4200
4200/4 = 1050
so she donated 25% to charity
Every number will have only 3 digits. In the ones place, there are 5 choices. For every choice of digit made in the ones place, there are 8 possible choices for the hundreds place (you can choose from 1-9, omitting whatever is used in the ones place), and there are 8 possible choices for the tens place (you can choose from 0-9, omitting whatever has already been used elsewhere).
So there are

such numbers.
Answer:
9
Step-by-step explanation:
Answer: the bus would be used 30 times for the monthly costs to be the same.
Step-by-step explanation:
Let x represent the number of times in a month for which the bus must be used so the total monthly cost is the same with the book as it is without it.
The bus fare without a coupon book is $1.50. This means that the total monthly cost of using the bus for x times without a coupon book is 1.5x
A coupon book cost $30.00 and with the coupon book, the fare is reduced $0.50. This means that the total monthly cost of using the bus for x times with a coupon book is
0.5x + 30
For the monthly costs to be the same,
1.5x = 0.5x + 30
1.5x - 0.5x = 30
x = 30
<h3>
Answer:</h3>
By <em>100 times</em>.
Step-by-step explanation:
Each time something is in Scientific Notation, to every power of 10 something is multiplied by, it grows by 10 times.
By knowing that, if both equations use the same starting number, you can minus the notation section from the larger value, to find the answer.
10^6 - 10^4 = 10^2 ---> 100 times.
Hope that helps, :)