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question:Charlie has 75% more apples than Dana, and Bella has 50% more apples than Dana. What is the relationship between the amounts of apples that Charlie and Bella have? textbf{(A)} Charlie has 10% more apples than Bella. textbf{(B)} Charlie has 16.67% more apples than Bella. textbf{(C)} Charlie has 25% more apples than Bella. textbf{(D)} Charlie has 33.33% more apples than Bella. textbf{(E)} Charlie has 50% more apples than Bella.
answer:Let's denote the amount of apples Dana has as D. According to the problem, Charlie has 75% more apples than Dana, and Bella has 50% more apples than Dana. We can express the amounts of apples Charlie and Bella have in terms of D. 1. **Calculate the amount of apples Charlie has:** Charlie has 75% more apples than Dana. This can be expressed as: [ C = D + 0.75D = 1.75D ] 2. **Calculate the amount of apples Bella has:** Bella has 50% more apples than Dana. This can be expressed as: [ B = D + 0.50D = 1.50D ] 3. **Find the relationship between the amounts of apples Charlie and Bella have:** To find how much more apples Charlie has compared to Bella, we calculate the difference and then find what percentage this difference is of Bella's amount: [ C - B = 1.75D - 1.50D = 0.25D ] To find this as a percentage of Bella's amount: [ text{Percentage} = left(frac{0.25D}{1.50D}right) times 100% = frac{0.25}{1.50} times 100% = frac{1}{6} times 100% approx 16.67% ] Thus, Charlie has approximately 16.67% more apples than Bella. Therefore, the correct answer is textbf{(B)}. The final answer is boxed{textbf{(B)}}
question:Three friends buy different bicycles at a store. Here are the original prices and the consecutive percentage reductions for each bicycle: 1. Bicycle A was originally priced at 600. It receives a 20% reduction, followed by a 15% reduction, and then a final 10% reduction. 2. Bicycle B was originally priced at 800. It receives a 25% reduction, followed by a 20% reduction, and then a final 5% reduction. 3. Bicycle C was originally priced at 1000. It receives a 30% reduction, followed by a 10% reduction, and then a final 25% reduction. Calculate the equivalent overall percentage reduction for each bicycle due to the consecutive discounts applied.
answer:To calculate the equivalent overall percentage reduction for each bicycle, we need to apply each discount consecutively and then determine the overall percentage reduction from the original price. Let's start with Bicycle A: 1. Bicycle A (600 original price): - First reduction: 20% of 600 = 120, so the new price is 600 - 120 = 480. - Second reduction: 15% of 480 = 72, so the new price is 480 - 72 = 408. - Third reduction: 10% of 408 = 40.80, so the final price is 408 - 40.80 = 367.20. The overall reduction for Bicycle A is 600 - 367.20 = 232.80. The equivalent overall percentage reduction is (232.80 / 600) * 100% = 38.8%. Now, Bicycle B: 2. Bicycle B (800 original price): - First reduction: 25% of 800 = 200, so the new price is 800 - 200 = 600. - Second reduction: 20% of 600 = 120, so the new price is 600 - 120 = 480. - Third reduction: 5% of 480 = 24, so the final price is 480 - 24 = 456. The overall reduction for Bicycle B is 800 - 456 = 344. The equivalent overall percentage reduction is (344 / 800) * 100% = 43%. Finally, Bicycle C: 3. Bicycle C (1000 original price): - First reduction: 30% of 1000 = 300, so the new price is 1000 - 300 = 700. - Second reduction: 10% of 700 = 70, so the new price is 700 - 70 = 630. - Third reduction: 25% of 630 = 157.50, so the final price is 630 - 157.50 = 472.50. The overall reduction for Bicycle C is 1000 - 472.50 = 527.50. The equivalent overall percentage reduction is (527.50 / 1000) * 100% = 52.75%. So, the equivalent overall percentage reductions for each bicycle are: - Bicycle A: 38.8% - Bicycle B: 43% - Bicycle C: boxed{52.75%}
question:Given that α is an angle in the second quadrant, f(α)= frac{sin (πα)tan (απ)}{sin (π+α)cos (2πα)tan (α)}. (I) Simplify f(α); (II) If cos (α frac{3π}{2})=frac{1}{3}, find the value of f(α).
answer:(I) To simplify f(α), we first rewrite the trigonometric functions using angle identities: f(α)= frac{sin (π-α)tan (-α-π)}{sin (π+α)cos (2π-α)tan (-α)} Since α is in the second quadrant, we know that sin α > 0 and cos α < 0. Using the identities sin(π-α) = sin α, tan(-α-π) = -tan α, sin(π+α) = -sin α, cos(2π-α) = cos α, and tan(-α) = -tan α, we can simplify the expression: f(α)= frac{sin α(-tan α)}{-sin αcos α(-tan α)} Now, cancel out the common factors: require{cancel}f(α)=frac{cancel{sin α}(-cancel{tan α})}{-cancel{sin α}cos α(-cancel{tan α})}=-frac{1}{cos α} (II) Given that cos (α- frac{3π}{2})=-frac{1}{3}, we first use the cofunction identity cos(α- frac{3π}{2}) = sin α: sin α = -frac{1}{3} However, since α is an angle in the second quadrant, we know that sin α > 0. Therefore, there is a sign error in the given solution. The correct identity should be: cos left(frac{3π}{2} - αright) = sin α Now we can correctly find the value of sin α: sin α = frac{1}{3} Next, we find the value of cos α using the Pythagorean identity: cos α = -sqrt{1-sin^2 α} = -sqrt{1-left(frac{1}{3}right)^2} = -frac{2sqrt{2}}{3} Finally, we substitute the value of cos α in the simplified expression for f(α): f(α)=-frac{1}{cos α}=-frac{1}{-frac{2sqrt{2}}{3}}=boxed{frac{3sqrt{2}}{4}}
question:A circle with a radius of 2cm, its circumference and area are ( ) A: Equal B: Circumference is greater C: Numerically equal, but units differ D
answer:Solution: The circumference of the circle: 3.14 times 2 times 2 = 3.14 times 4 = 12.56 (CM); The area of the circle: 3.14 times 2^2 = 3.14 times 4 = 12.56 (CM^2); Therefore, the numerical values are equal, but the units are different. Hence, the correct option is: boxed{C}. This can be determined by calculating based on the formulas for the circumference and area of a circle. This tests the formula for the circumference of a circle: C = 2pi r. It also tests the formula for the area of a circle: S = pi r^2.