Higher Plus

On a histogram, a 4-wide bar and a 12-wide bar have the same frequency density of 2.5. How many more values are in the wider class?

Simplify 80 + 45, giving your answer in the form a b.Simplify sqrt(80) + sqrt(45), giving your answer in the form a sqrt(b).

Prove that the sum of 9 consecutive integers is always a multiple of 9. State the simplified sum you would use.

A cyclist speeds up steadily from 4 m/s to 8 m/s over 10 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.