Higher Plus

On a histogram, a 10-wide bar and a 20-wide bar have the same frequency density of 1.5. How many more values are in the wider class?

Rationalise the denominator of 15/5, giving your answer in its simplest form.Rationalise the denominator of 15/sqrt(5), giving your answer in its simplest form.

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

A tram runs at 12 m/s for 20 s, then slows steadily to rest over 4 s. Work out its average speed for the whole journey, to 2 decimal places.

The point (8, 15) lies on the circle x² + y² = 289. Work out the gradient of the tangent to the circle at that point.The point (8, 15) lies on the circle x^2 + y^2 = 289. Work out the gradient of the tangent to the circle at that point.