Higher Plus

On a histogram, a 5-wide bar and a 15-wide bar have the same frequency density of 3. How many more values are in the wider class?

x = 71 and y = 20, each correct to the nearest whole number. Work out the upper bound of x - y.

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

A tram runs at 14 m/s for 10 s, then slows steadily to rest over 6 s. Work out its average speed for the whole journey, to 2 decimal places.

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.