A high speed train travels a distance of 503 km in 3 hours. The distance is measured correct to the nearest kilometre.
The time is measured correct to the nearest minute.
By considering bounds, work out the average speed, in km/minute, of the
train to a suitable degree of accuracy.
You must show your working.
To gain full marks you need to give a one-sentence reason for
your final answer - the words 'both' and 'round' should be in your sentence.

To find the extreme values of a function f(x.y) on a curve x-x(t), y y(t), treat f as a function of the single variable t and use the chain rule to find where df/dt is zero. in any other single-variable case, the extreme values of f are then found among the values at the critical points (points where df/dt is zero or fails to exist), and endpoints of the parameter domain. find the absolute maximum and minimum values of the following function on the given curves. use the parametric equations x=2cos t, y 2 sin t functions: curves: i) the semicircle x4,y20 i) the quarter circle x2+y-4, x20, y20 b, g(x,y)=xy

He concluded that a heavier object dropped from the same height as a lighter object will land

The volume of a sphere is increased by 6%. calculate the corresponding percentage increased in it area.