Higher Plus

A bag holds 9 counters, r of them red. Two are taken without replacement and P(both red) = 7/12. Work out r.

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

A block has mass 730 g (to the nearest 10 g) and volume 21 cm³ (to the nearest cm³). Work out the upper bound of its density, to 2 decimal places.A block has mass 730 g (to the nearest 10 g) and volume 21 cm^3 (to the nearest cm^3). Work out the upper bound of its density, to 2 decimal places.

Simplify (x² + 7x - 8)/(x + 8).Simplify (x^2 + 7x - 8)/(x + 8).

y is directly proportional to x. When x = 4, y = 10. Work out y when x = 9.y is directly proportional to sqrt(x). When x = 4, y = 10. Work out y when x = 9.