Let the number of boys be 3x and girls be 4x. Given 4x = 28, we find x = 7. Thus, boys = 3x = 3*7 = 21.

Let the number of shares of B be x. Then, 3/2 = 60/x => x = (2/3) * 60 = 40 shares of B.

Let A's age be 3x and B's age be 4x. Then, 3x + 4x = 56. Solving gives x = 8, so A's age = 3x = 24 years.

If A's age is 4x and B's age is 5x, then 4x = 20 => x = 5. Therefore, B's age = 5x = 25.

Let the sides be 3x and 4x. Then, 3x + 4x = 70, 7x = 70, x = 10. Therefore, the shorter side = 3x = 3*10 = 30.

Let apples be 3x and oranges be 5x. Given 5x = 40, x = 8. Therefore, apples = 3x = 3*8 = 24.

Let the cost of stock B be x. Then, 3/5 = 90/x => x = (90 * 5) / 3 = $150

Let the speeds be 5x and 7x. Faster car's speed = 70 km/h. Slower car's speed = (5/7)*70 = 50 km/h. Distance = speed * time = 50 * 2 = 100 km.

Speed of faster train = 280/4 = 70 km/h. Speed of slower train = (5/7)*70 = 50 km/h. Distance = speed * time = 50*4 = 200 km.

Let the numbers be 7x and 9x. Then, 7x + 9x = 80, 16x = 80, x = 5. Therefore, the smaller number = 7x = 7*5 = 35.

Current sales of Product C are 400, increasing by 50% gives 600.

Principal = (Simple Interest × 100) / (Rate × Time) = (200 × 100) / (5 × 4) = $1000.

Principal = (Simple Interest × 100) / (Rate × Time) = (150 × 100) / (5 × 3) = $1000.

Principal = (Interest * 100) / (Rate * Time) = (240 * 100) / (6 * 4) = $1000.

Principal = (Interest × 100) / (Rate × Time) = (240 × 100) / (6 × 4) = $1000.

The square root of 16 is 4, since 4 * 4 = 16.

The square root of 36 is 6, since 6 * 6 = 36.

The square root of 81 is 9, since 9 * 9 = 81.

The number is 225, since 15 * 15 = 225.

The number is 64, since 8 * 8 = 64.

Let B's age be x. Then A's age is x + 10. So, x + (x + 10) = 60. Solving gives x = 25, hence A = 35.

Let B's age be x. Then A's age is x + 10. So, x + (x + 10) = 60. Solving gives x = 25. Therefore, A is 35 and B is 25.

At 1:50, the hour hand is at 95 degrees (1 hour * 30 degrees + 50 minutes * 0.5 degrees) and the minute hand is at 300 degrees (50 minutes * 6 degrees). The angle between them is |95 - 300| = 205 degrees.

At 2:30, the hour hand is at 75 degrees (2 hours * 30 degrees + 30 minutes * 0.5 degrees) and the minute hand is at 180 degrees (30 minutes * 6 degrees). The angle between them is |75 - 180| = 105 degrees.

Product C accounts for 20% of total revenue, which is $400.

Banker's Discount = True Discount * (1 + (Rate * Time)) = 150 * (1 + (10 * 5/12)) = Rs. 200.

True Discount = Sum * Rate / (100 + Rate). Let Sum = x. Then, 120 = x * 6 / (100 + 6*3). Solving gives x = $2400.

True Discount = Sum * Rate / (100 + Rate). Let Sum = x. Then, 150 = x * 5 / (100 + 5). Solving gives x = $2500.

True Discount = Sum * Rate / (100 + Rate). Let Sum = x. Then, 80 = x * 10 / (100 + 10). Solving gives x = $1000.

True Discount = Present Worth * Rate * Time / 100. 150 = 850 * Rate * 1 / 100. Rate = (150 * 100) / 850 = 17.65%, approximately 15%.