Daily Practice - Higher Plus

A bag holds 11 counters, r of them red. Two are taken without replacement and P(both red) = 28/55. Work out r.

A histogram has four 10-wide classes from 0, with frequency densities 0.5, 2, 3, 1. Which class contains the median?

A block has mass 900 g (to the nearest 10 g) and volume 11 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 11 cm^3 (to the nearest cm^3). Work out the upper bound of its density, to 2 decimal places.

Solve x² + y² = 289 and y = x + 7 simultaneously.Solve x^2 + y^2 = 289 and y = x + 7 simultaneously.

y is inversely proportional to x². When x = 4, y = 75. Work out y when x = 5.y is inversely proportional to x^2. When x = 4, y = 75. Work out y when x = 5.