Higher Plus

On a histogram, a 4-wide bar and a 16-wide bar have the same frequency density of 2. How many more values are in the wider class?

Simplify 80 + 180, giving your answer in the form a b.Simplify sqrt(80) + sqrt(180), giving your answer in the form a sqrt(b).

Solve x² + y² = 225 and y = x + 3 simultaneously.Solve x^2 + y^2 = 225 and y = x + 3 simultaneously.

A cyclist speeds up steadily from 3 m/s to 15 m/s over 12 seconds. Use the area under the velocity-time graph to find the distance travelled.

The point (9, 40) lies on the circle x² + y² = 1681. Work out the gradient of the tangent to the circle at that point.The point (9, 40) lies on the circle x^2 + y^2 = 1681. Work out the gradient of the tangent to the circle at that point.