Higher Plus

A bag holds 3 red and n blue counters. The probability of taking a red is 3/10. Work out n.

A histogram has four 20-wide classes from 0, with frequency densities 3, 2, 0.5, 1. Which class contains the median?

A block has mass 900 g (to the nearest 10 g) and volume 22 cm³ (to the nearest cm³). Work out the upper bound of its density, to 2 decimal places.A block has mass 900 g (to the nearest 10 g) and volume 22 cm^3 (to the nearest cm^3). Work out the upper bound of its density, to 2 decimal places.

f(x) = 2x + 6 and g(x) = 6x + 3. Work out fg(6).

y is inversely proportional to x². When x = 5, y = 32. Work out y when x = 4.y is inversely proportional to x^2. When x = 5, y = 32. Work out y when x = 4.