Higher Plus

A bag holds 5 counters, r of them red. Two are taken without replacement and P(both red) = 3/10. Work out r.

On a histogram the bar for 30 < x ≤ 40 has a frequency density of 1.5. How many values are in that class?On a histogram the bar for 30 < x <= 40 has a frequency density of 1.5. How many values are in that class?

Expand and simplify (4 + 3)(4 - 3).Expand and simplify (4 + sqrt(3))(4 - sqrt(3)).

Solve x² + y² = 169 and y = x - 7 simultaneously.Solve x^2 + y^2 = 169 and y = x - 7 simultaneously.

y is directly proportional to x³. When x = 2, y = 48. Work out y when x = 5.y is directly proportional to x^3. When x = 2, y = 48. Work out y when x = 5.