For mutually exclusive events, P(C or D) = P(C) + P(D) = 0.2 + 0.3 = 0.5.

The probability that it will not rain is 1 - 0.7 = 0.3.

6 and 7 are consecutive integers whose product is 42, not 72.

For the product to be a multiple of 15, at least one of the numbers must be a multiple of 5.

According to Vieta's formulas, the sum of the roots p and q is -b/a and the product is c/a.

For equal roots, the discriminant must be zero: (-4)^2 - 4*1*k = 0, leading to k = 4.

The constant ratio of consecutive terms in a geometric series is called the common ratio.

According to Vieta's formulas, the sum of the roots p + q is equal to -(-5) = 5.

The percentage increase from Q2 (200 units) to Q3 (300 units) is 50%.

If Product B sold 600 units in Q3, a 20% decrease would result in 480 units.

If Product D sold 200 units in Q3, doubling that would result in 400 units in Q4.

If Product D's sales in Q3 were 200 units, doubling it would result in 400 units.

A triangle with sides in the ratio 3:4:5 is a right-angled triangle, as it satisfies the Pythagorean theorem.

Using SI = PRT, we have 150 = P * 0.05 * 3. Solving for P gives P = 1000.

If all squares are rectangles, it implies that there are rectangles that are not squares, thus some rectangles are not squares.

The sum of the first n terms S_n = n/2 * (2a + (n-1)d). By differentiating S_n with respect to n, we can find the common difference. The common difference is 3.

The common difference can be found by calculating S_n - S_(n-1). Here, S_n = 3n^2 + 2n and S_(n-1) = 3(n-1)^2 + 2(n-1). The difference simplifies to 4.

'a' represents the first term of the arithmetic series.

Let the first term be a. The sum of the first three terms is a + 2a + 4a = 7a. Setting 7a = 14 gives a = 2.

Let the integers be x, x+1, and x+2. Their sum is x + (x + 1) + (x + 2) = 3x + 3 = 72. Solving gives 3x = 69, so x = 23.

All pairs listed are multiples of 7 that sum to 56.

The reciprocals are 1, 4, and 9. The common difference is 4 - 1 = 3.

The reciprocals of the terms are 1/3, 1/6, and 1/x. Since they form an arithmetic progression, we can set up the equation: 1/6 - 1/3 = 1/x - 1/6, solving gives x = 12.

Product A shows a consistent upward trend, indicating a significant increase by Q4.

The complement of set A consists of elements in the universal set U that are not in set A. Therefore, the complement is {1, 3, 5}.

Let the smaller angle be x. Then the larger angle is x + 10. Since they are complementary, x + (x + 10) = 90. Solving gives x = 40 degrees, so the angles are 40 and 50 degrees.

If two angles are equal and their sum is 180 degrees, they are straight angles, each measuring 90 degrees.

The centers of two intersecting circles are equidistant from the points of intersection.

Circles that intersect at two points are said to be secant to each other.

The combinations that give a sum of 7 are (1,6), (2,5), (3,4), (4,3), (5,2), (6,1), totaling 6 combinations. The total outcomes are 36, so the probability is 6/36 = 1/6.