An airplane is 5,000 ft above ground and has to land on a runway that is 7,000 ft away as shown above. Let x be the angle the pilot takes to land the airplane at the beginning of the runway. Which equation is a correct way to calculate x?
- A. sin x = 5000/7000
- B. sin x = 7000/5000
- C. tan x = 5000/7000
- D. tan x = 7/5000
Correct Answer & Rationale
Correct Answer: C
To determine the angle \( x \) for landing, we need to consider the relationship between the height of the airplane and the distance to the runway. The height (5000 ft) is the opposite side of the right triangle formed, while the distance to the runway (7000 ft) is the adjacent side. The tangent function relates these two sides, hence \( \tan x = \frac{\text{opposite}}{\text{adjacent}} \) leads to \( \tan x = \frac{5000}{7000} \). Option A incorrectly uses the sine function, which relates the opposite side to the hypotenuse. Option B also misapplies sine but swaps the sides, leading to an incorrect ratio. Option D incorrectly uses tangent but misrepresents the sides, making it invalid. Thus, option C accurately represents the relationship needed to calculate angle \( x \).
To determine the angle \( x \) for landing, we need to consider the relationship between the height of the airplane and the distance to the runway. The height (5000 ft) is the opposite side of the right triangle formed, while the distance to the runway (7000 ft) is the adjacent side. The tangent function relates these two sides, hence \( \tan x = \frac{\text{opposite}}{\text{adjacent}} \) leads to \( \tan x = \frac{5000}{7000} \). Option A incorrectly uses the sine function, which relates the opposite side to the hypotenuse. Option B also misapplies sine but swaps the sides, leading to an incorrect ratio. Option D incorrectly uses tangent but misrepresents the sides, making it invalid. Thus, option C accurately represents the relationship needed to calculate angle \( x \).
Other Related Questions
The price P, in dollars, that a store sets for an item is given by the equation P = C + 1/10 * C where C dollars is the store's cost for the item. If the store sets a price of $55.00 for an item, what is the store's cost for the item?
- A. $50.00
- B. $54.90
- C. $55.10
- D. $60.50
Correct Answer & Rationale
Correct Answer: A
To find the store's cost \( C \), we start with the equation \( P = C + \frac{1}{10}C \). This can be simplified to \( P = 1.1C \). Given that \( P = 55 \), we can set up the equation \( 55 = 1.1C \). Solving for \( C \) gives \( C = \frac{55}{1.1} = 50 \). Option A ($50.00) is correct, as it satisfies the equation. Option B ($54.90) incorrectly suggests a cost that would lead to a higher price than $55 when applying the markup. Option C ($55.10) implies a cost greater than the set price, which is illogical. Option D ($60.50) is also incorrect as it would result in a price far exceeding $55, making it unfeasible.
To find the store's cost \( C \), we start with the equation \( P = C + \frac{1}{10}C \). This can be simplified to \( P = 1.1C \). Given that \( P = 55 \), we can set up the equation \( 55 = 1.1C \). Solving for \( C \) gives \( C = \frac{55}{1.1} = 50 \). Option A ($50.00) is correct, as it satisfies the equation. Option B ($54.90) incorrectly suggests a cost that would lead to a higher price than $55 when applying the markup. Option C ($55.10) implies a cost greater than the set price, which is illogical. Option D ($60.50) is also incorrect as it would result in a price far exceeding $55, making it unfeasible.
In the figure above, what is the average (arithmetic mean) of w, x, y, and z?
- A. 90
- B. 100
- C. 120
- D. It cannot be determined from the information given.
Correct Answer & Rationale
Correct Answer: D
To find the average of w, x, y, and z, all values must be known. Option D is valid since the problem does not provide specific values or relationships between these variables, making it impossible to calculate their average. Option A (90), Option B (100), and Option C (120) suggest definitive averages, but without concrete data on w, x, y, and z, these answers cannot be substantiated. Each of these options assumes values that may not exist or be accurate, highlighting the necessity of complete information for such calculations.
To find the average of w, x, y, and z, all values must be known. Option D is valid since the problem does not provide specific values or relationships between these variables, making it impossible to calculate their average. Option A (90), Option B (100), and Option C (120) suggest definitive averages, but without concrete data on w, x, y, and z, these answers cannot be substantiated. Each of these options assumes values that may not exist or be accurate, highlighting the necessity of complete information for such calculations.
(a ^ 9 * b ^ 12)/(a ^ 3 * b) =
- A. a ^ 3 * b ^ 11
- B. a ^ 6 * b ^ 12
- C. a ^ 3 * b ^ 12
- D. a ^ 6 * b ^ 11
Correct Answer & Rationale
Correct Answer: D
To simplify the expression \((a^9 * b^{12})/(a^3 * b)\), apply the laws of exponents. For the \(a\) terms, subtract the exponents: \(9 - 3 = 6\), giving \(a^6\). For the \(b\) terms, also subtract the exponents: \(12 - 1 = 11\), resulting in \(b^{11}\). Thus, the simplified expression is \(a^6 * b^{11}\). Option A is incorrect because it miscalculates the exponent of \(b\). Option B incorrectly maintains the exponent of \(b\) at 12. Option C fails to adjust the exponent of \(a\) correctly. Only option D accurately reflects the simplification.
To simplify the expression \((a^9 * b^{12})/(a^3 * b)\), apply the laws of exponents. For the \(a\) terms, subtract the exponents: \(9 - 3 = 6\), giving \(a^6\). For the \(b\) terms, also subtract the exponents: \(12 - 1 = 11\), resulting in \(b^{11}\). Thus, the simplified expression is \(a^6 * b^{11}\). Option A is incorrect because it miscalculates the exponent of \(b\). Option B incorrectly maintains the exponent of \(b\) at 12. Option C fails to adjust the exponent of \(a\) correctly. Only option D accurately reflects the simplification.
A playground at a mall is in the shape of a rectangle, and there is a 144 foot long fence around it. If the rectangle is 6 feet longer than it is wide, what is the width, in feet, of the rectangle?
- A. 33
- B. 39
- C. 69
- D. 75
Correct Answer & Rationale
Correct Answer: A
To find the width of the rectangle, let the width be represented as \( w \). The length, being 6 feet longer, can be expressed as \( w + 6 \). The perimeter of a rectangle is given by the formula \( P = 2(l + w) \). Here, the perimeter is 144 feet, leading to the equation \( 2(w + (w + 6)) = 144 \). Simplifying this gives \( 2(2w + 6) = 144 \), which reduces to \( 4w + 12 = 144 \), and further simplifies to \( 4w = 132 \), resulting in \( w = 33 \). Option B (39) is incorrect as it gives a perimeter of 156 feet. Option C (69) would lead to an impossible perimeter of 150 feet. Option D (75) results in a perimeter of 162 feet, which exceeds the given value. Thus, only option A satisfies all conditions, confirming the width as 33 feet.
To find the width of the rectangle, let the width be represented as \( w \). The length, being 6 feet longer, can be expressed as \( w + 6 \). The perimeter of a rectangle is given by the formula \( P = 2(l + w) \). Here, the perimeter is 144 feet, leading to the equation \( 2(w + (w + 6)) = 144 \). Simplifying this gives \( 2(2w + 6) = 144 \), which reduces to \( 4w + 12 = 144 \), and further simplifies to \( 4w = 132 \), resulting in \( w = 33 \). Option B (39) is incorrect as it gives a perimeter of 156 feet. Option C (69) would lead to an impossible perimeter of 150 feet. Option D (75) results in a perimeter of 162 feet, which exceeds the given value. Thus, only option A satisfies all conditions, confirming the width as 33 feet.