Tag: math & puzzles

Questions Related to math & puzzles

After how many days will half of the pool be covered by the water-lily?

  1. 10

  2. 19

  3. 15

  4. 11


Correct Option: B

How old are John and Julia?

  1. 40 and 30

  2. 30 and 40

  3. 80 and 60

  4. 60 and 80


Correct Option: B

A company makes a profit equal to 25% of its sales. The profit is shared equally among the 4 owners of the company. If the company generates sales of $5,000,000, how much money does each one of the owners get?

  1. 12,500

  2. 312,500

  3. 500,000

  4. 1,250,000


Correct Option: B

The two legs of a right triangle measure 6 and 8 inches respectively. What is the area of the circle that contains all 3 vertices of the triangle?

  1. 24Pi

  2. 25Pi

  3. 36Pi

  4. 64Pi


Correct Option: B

A cylinder of radius 5 cm is inserted within a cylinder of radius 10 cm. The two cylinders have the same height of 20 cm. What is the volume of the region between the two cylinders?

  1. 100Pi

  2. 500Pi

  3. 1000Pi

  4. 1500Pi


Correct Option: D

A cone made of cardboard has a vertical height of 8 cm and a radius of 6 cm. If this cone is cut along the slanted height to make a sector, what is the central angle, in degrees, of the sector?

  1. 216

  2. 180

  3. 90

  4. 36


Correct Option: A

As x increases from Pi/4 to 3Pi/4, |sin(2x)|

  1. always increases

  2. always decreases

  3. increases then decreases

  4. decreases then increases


Correct Option: D

AI Explanation

To answer this question, let's analyze the given expression |sin(2x)| as x increases from π/4 to 3π/4.

The function sin(2x) is an oscillating function with a period of π. That means it completes one full cycle from 0 to 2π.

When x increases from π/4 to 3π/4, we can see that the values of 2x also increase. Let's consider the values of 2x within the given range:

When x = π/4, 2x = 2(π/4) = π/2 When x = 3π/4, 2x = 2(3π/4) = 3π/2

Now, let's evaluate the absolute value of sin(2x) at these two points:

|sin(π/2)| = 1 |sin(3π/2)| = |sin(π + π/2)| = |sin(π/2)| = 1

We can observe that the absolute value of sin(2x) is equal to 1 at both x = π/4 and x = 3π/4.

Therefore, as x increases from π/4 to 3π/4, |sin(2x)| does not always increase or always decrease. Instead, it remains constant at 1 throughout this interval.

Hence, the correct answer is D) decreases then increases.