Higher Plus

On a histogram, a 5-wide bar and a 15-wide bar have the same frequency density of 2.5. 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 + x < 0.Solve x^2 + x < 0.

A cyclist speeds up steadily from 8 m/s to 23 m/s over 8 seconds. Use the area under the velocity-time graph to find the distance travelled.

The point (12, 16) lies on the circle x² + y² = 400. Work out the gradient of the tangent to the circle at that point.The point (12, 16) lies on the circle x^2 + y^2 = 400. Work out the gradient of the tangent to the circle at that point.