Answer:
So the number of total combinations is 35.
Step-by-step explanation:
We know that Ellen must take 4 courses this semester. She has a list of 3 math courses and 4 science courses.
Therefore, she have total 7 courses.
So, we calculate the number of combinations to choose 4 out of 7 courses.
We get:

So the number of total combinations is 35.
Answer:
2 paperclips for 1 cent
Step-by-step explanation:
1 electron has a mass of 9.1 X 10-31 kg. How many electrons n does it take to make 1 kg?
(1 e)/(9.1 X 10-31 kg) = n/(1 kg)
So, n = 1.10 X 1030 electrons
Each electron has a charge of 1.6 X 10-19 C, where C stands for Coulombs. So, the n electrons have a charge of q = ne = (1.10 X 1030 electrons) X (1.6 X 10-19 C/electron) = 1.76 X 1011 C.
Answer:
If you know the base and area of the triangle, you can divide the base by 2, then divide that by the area to find the height. To find the height of an equilateral triangle, use the Pythagorean Theorem, a^2 + b^2 = c^2.
Answer:
The first option.
Because we're solving for the price of each gallon, x will represent the cost of each gallon. Since 8.4 is the total amount of gallons, multiply 8.4 and x to get $23.94. Solve for x by dividing 23.94 to get $2.85 per gallon. To check this, substitute 2.85 for x into the equation: 8.4 (2.85) = 23.94