The depreciation amount is 20% of $20,000, which is $4,000. Therefore, the value after one year is $20,000 - $4,000 = $16,000.

There are 13 hearts and 4 queens, but one queen is a heart. So, the probability is (13 + 4 - 1)/52 = 16/52 = 4/13.

There are 13 hearts and 4 queens, but one of the queens is a heart. Thus, the probability is (13 + 4 - 1)/52 = 16/52 = 4/13.

Using the Rule of 72, time = 72/r = 72/10 = 7.2 years.

Using A = P(1 + r)^t, we rearrange to find P = A / (1 + r)^t. Thus, P = 5000 / (1.12)^3 = $4000.

Using the formula A = P(1 + r)^n, we can set up the equation 3P = P(1 + r)^15. Solving for r gives approximately 6%.

The last term of an AP is given by a + (n-1)d. Here, 100 = 10 + (20-1)d. Solving gives d = 5.

The common difference d can be calculated using the formula for the nth term: a + (n-1)d = last term. Here, 12 + 9d = 48, solving gives d = 4.

The sum of the first n terms S_n = n/2 * (2a + (n-1)d). Here, S_10 = 10/2 * (2*7 + 9*2) = 5 * (14 + 18) = 5 * 32 = 160.

The new number is (original number * 2), which gives a remainder of (8 * 2) = 16, and 16 divided by 15 gives a remainder of 1.

Let x be the liters of 25% solution. The equation is 0.25x + 0.5(10) = 0.4(x + 10). Solving gives x = 15 liters.

Area of a circle = πr². Using π ≈ 3.14, Area = 3.14 × (7)² = 3.14 × 49 = 153.86 cm², which rounds to 154 cm².

Area of a circle = πr² = (22/7) × (7)² = (22/7) × 49 = 154 cm².

Area = πr² = 3.14 × (7)² = 3.14 × 49 = 153.86 cm², which rounds to 154 cm².

Radius = diameter/2 = 5 m. Area = πr² = 3.14 × 5² = 78.5 m².

Number of girls = 40% of 30 = 12. Therefore, number of boys = 30 - 12 = 18.

25% of 120 is 30, so the number of employees not in the sales department is 120 - 30 = 90.

Profit = 20% of $50,000 = 0.20 * 50,000 = $10,000.

Profit = 20% of $500,000 = 0.2 * 500,000 = $100,000.

Profit amount = 25% of $200,000 = 0.25 * 200,000 = $50,000.

Selling Price = Cost Price + Profit = 200 + (30% of 200) = 200 + 60 = $260.

Profit = 30% of $500,000 = 0.3 * 500,000 = $150,000.

Selling Price = Cost Price + Profit = 200 + (25% of 200) = 200 + 50 = $250.

Volume of cone = (1/3)πr²h; Volume of cylinder = πr²h. Therefore, cone's volume is one-third of the cylinder's volume.

Volume of a cone = (1/3)πr²h = (1/3)π(2)²(6) = (1/3)π(4)(6) = 8π cm³.

The surface area of a cone is given by SA = πr(r + l), where l is the slant height. Here, l = √(r² + h²) = √(2² + 6²) = √40. Thus, SA = π(2)(2 + √40) = 20π.

The surface area of a cone is given by SA = πr(r + l), where l is the slant height. Here, l = √(3² + 4²) = 5, so SA = π(3)(3 + 5) = 24π.

The volume of a cone is given by V = (1/3)πr²h. Here, r = 4 and h = 9, so V = (1/3)π(4)²(9) = 48π.

The surface area of a cone is given by SA = πr(r + l), where l is the slant height. Here, l = √(5² + 12²) = 13, so SA = π(5)(5 + 13) = 90π cm².

Volume = (1/3)πr²h = (1/3) * 3.14 * (4)² * 9 = 113.04 cm³.