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.

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

A block has mass 470 g (to the nearest 10 g) and volume 17 cm³ (to the nearest cm³). Work out the upper bound of its density, to 2 decimal places.A block has mass 470 g (to the nearest 10 g) and volume 17 cm^3 (to the nearest cm^3). Work out the upper bound of its density, to 2 decimal places.

Solve x² + y² = 676 and y = x + 14 simultaneously.Solve x^2 + y^2 = 676 and y = x + 14 simultaneously.

y is inversely proportional to x². When x = 5, y = 16. Work out y when x = 2.y is inversely proportional to x^2. When x = 5, y = 16. Work out y when x = 2.