Which of the following is a human-made water body

The function f(x)=x³ −62x²+ax+9 has a local maximum at x=1. Then the value of a is:

The ratio of the length and area of a rectangle is 1:39. And the ratio of length and breadth 4:3. Find the perimeter of ​​the rectangle.

Calculate the percentage contribution of the South branch's total revenue to the company's total revenue over the three years (2021-2023).

What will be come in place of (?) in the given number series.

7, 11, 15, 19, ?, 27

The ratio of milk and water in a mixture of 28 litres is 4 : 3. Find the quantity of milk in the mixture? 

Solve the equation: sin x = 1/2, 0 ≤ x ≤ 2π

Find the sum of areas of surfaces of an open chalk box that is in the shape of Cuboid.

Rs. 156 is to be shared among 40 students, if each girl receives Rs.4.50, and boy receive Rs.3.50. Find the ratio of number of boys and girls.

Compute P(AǀB), if P(B) = 1.0 and P(A∩B) = 0.64