Let the number of hour it took them to have completed the same number of problems be x, then
15 + 10x = 9 + 12x
12x - 10x = 15 - 9
2x = 6
x = 6/2 = 3
After 3 hours, they must have completed the same number of homeworks.
Answer: 11/12
Step-by-step explanation:
1. To solve this problem you can transform the mixed numbers given in the problem to fractions, as you can see below:
3 2/3=(3*3+2)/3=11/3
2 3/4=(4*2+3)/4=11/4
2. Now you must make the substraction of the fraction:
11/3-11/4=11/12
3. Therefore, the answer is 11/12
$72 - $30 = $42
It increased $42.
Now take this number and divide by the original number (first):
42 ÷ 30
This is 1.4, let's convert this to a percentage.
We now times it by 100
1.4 × 100
The answer is 140%
Answer:

And then replacing in the total probability formula we got:

And rounded we got 
That represent the probability that it rains over the weekend (either Saturday or Sunday)
Step-by-step explanation:
We can define the following notaton for the events:
A = It rains over the Saturday
B = It rains over the Sunday
We have the probabilities for these two events given:

And we are interested on the probability that it rains over the weekend (either Saturday or Sunday), so we want to find this probability:

And for this case we can use the total probability rule given by:

And since we are assuming the events independent we can find the probability of intersection like this:

And then replacing in the total probability formula we got:

And rounded we got 
That represent the probability that it rains over the weekend (either Saturday or Sunday)