A rational number is an algebraic term expressed as a fraction. The fraction can also be in decimals but only if the decimal places are not repeating or not infinitely long. If they aren't, then these are called irrational numbers.
Let's try each of the choices:
A. The term 2/4 is a rational number. Now, when 0.3 or 3/10 is added to it, the sum would be 4/5 or 0.8. This is a rational number.
B. √7 is an irrational number because its exact value is 2.645751311.... Even if you add 0.3 to it, the answer would still be irrational
C. Obviously, this is an irrational number
D. The exact value of π is <span>3.14159...... If 0.3 is added to it, the answer would be 3.441592654. This is irrational.
Therefore, the answer is A.</span>
We need the total count of persons = 10+12+12+15 = 49 persons
We need the count of the target group, female or teaching assistants
= (10+12) professors + 12 male teaching assistants
= 22+12
= 34 persons
Assuming equal probability of choosing anyone from the 30 persons, the
probability of choosing a professor or a male
= 34/49
(For probability calculations, try to keep a fraction for as long as you can, because fractions are exact. Decimal are frequently approximate, for example in this case, 34/49=0.693877551020...... = 0.694 approximately)
Equation of a line is given by y - y1 = m(x - x1) where m is the slope and (x1, y1) is any point on the line.
y - (-2) = 4(x - 3)
y + 2 = 4x - 12
y = 4x - 12 - 2
y = 4x - 14
x=3, you can find this by using finding common bases for equation b because 243=3^5. Because of that you can get rid of three on both sides to get the equation 2x-1=5 and then just solve for x to get x=3. For the first equation 5^3=625 so that also proves x=3.
Sorry if my explanation is a little disorganized if you need more help feel free to ask
