The answer is 15/121.
Since we have red AND blue, that means that both of these events occur, so we will use the multiplication rule and multiply these two probabilities:
- A probability of choosing a red marble: 3/11. (because there are 3 marbles out of total 11 marbles)
- A probability of choosing a blue marble after the red one: 5/11. (because there are 3 marbles out of total 11 marbles; there are 11 in total again because the first marble has been returned)
So, P(red and blue) is 3/11 * 5/11 = (3*5)/(11*11) = 15/121
Answer: 
Step-by-step explanation:
Do you mean
? In that case just finish things inside the bracket first then multiply 2 inside.

Then multiply 2 inside the bracket.

Move 54 to other side then we get,




(Note: If this is not what you mean then please let me know.)
1908
Step-by-step explanation:2% of 1800 is 36 36 x 3 is 108 + 1800 =1908
Answer:
25 milliliters of 25% solution and 75 milliliters of 5% solution should be used.
Step-by-step explanation:
Since the druggist has to prepare 100 ml of a 10% solution, but has only 5% and 25% solutions, to determine the proportion of each solution that he must use to prepare the solution with the desired percentage, it is necessary to perform the following calculation:
25 x 1 + 5 x 0 = 25
25 x 0.9 + 5 x 0.1 = 23
25 x 0.8 + 5 x 0.2 = 21
25 x 0.7 + 5 x 0.3 = 19
25 x 0.6 + 5 x 0.4 = 17
25 x 0.5 + 5 x 0.5 = 15
25 x 0.4 + 5 x 0.6 = 13
25 x 0.3 + 5 x 0.7 = 11
25 x 0.2 + 5 x 0.8 = 9
Therefore, the percentage that the druggist must use will be between 20% and 30% of the 25% solution, and between 70% and 80% of the 5% solution, that is:
25 x 0.25 + 5 x 0.75 = 10
Therefore, the druggist should use a 25% solution at 25%, and a 75% solution at 5%: Thus, since 100 x 0.25 is equal to 25, 25 milliliters of 25% solution and 75 milliliters of 5% solution should be used.
I think the second option is right