Higher Plus

A bag holds 5 red and 9 blue counters. Two are taken without replacement. Given the first was red, what is the probability the second is blue?

On a histogram the bar for 20 < x ≤ 40 has a frequency density of 2.4. How many values are in that class?On a histogram the bar for 20 < x <= 40 has a frequency density of 2.4. How many values are in that class?

Expand and simplify (6 + 3)(6 - 3).Expand and simplify (6 + sqrt(3))(6 - sqrt(3)).

Solve x² + y² = 25 and y = x - 1 simultaneously.Solve x^2 + y^2 = 25 and y = x - 1 simultaneously.

y is directly proportional to x³. When x = 2, y = 32. Work out y when x = 3.y is directly proportional to x^3. When x = 2, y = 32. Work out y when x = 3.