Answer: Maria has 10 bills of 5€ and 10 bills of 10€.
She has a total of 150€.
Step-by-step explanation:
Let be "f" the number of 5€ bills that Maria has and "t" the number of 10€ bills that Maria has.
Set up a system of equations:

Use the Substitution method to solve the system of equations:
1. Solve for "f" from the first equation:

2. Substitute the equation obtained into the second equation and solve for "t".
Then:

3. Substitute the value of "t" into the equation
and evaluate:

Therefore, Maria has 10 bills of 5€ and 10 bills of 10 €.
So the total amount of money she has, is:

She has a total of 150€.
Answer:
4 : 10
Step-by-step explanation:
There are mistakes in the answer options attached. These are the correct ones.
a. The group that received the bottle of solution is the control group.
b. The group that received the bottle of solution that did not contain the ingredients that are meant to lessen wrinkles is the control group.
c. Both the groups are control groups.
d. Neither group is an control group.
Answer:
B. The group that received the bottle of solution that did not contain the ingredients that are meant to lessen wrinkles is the control group
Step-by-step explanation:
In an experiment of this type, the control group is the group that does not contain the treatment. So in this group The effect of the treatment unknown unlike the experimental group which gets the treatment that the researcher is trying to find it's effect.
I. Conclusion, the group that got bottles that did not contain Ingredients for wrinkles lessening is the control group.
If the question is asking how many trees can be planted with 6 cubic yards of compost, here is the solution.
6 divided by 1/6 means to take 6 wholes and break them into groups the size of 1/6.
One whole can be broken into 6 groups of 1/6 (6/6), so 6 wholes can be broken into 36 groups of 1/6 (6 x 6 = 36/6).
Mathematically, you will multiply 6 by 6/1 to get the 36.
You can plant 36 trees with 6 cubic yards of compost.