Question 1125616
A train travels 250 km at the speed of 60 km/hr and arrives ten minutes  later than schedule. At what speed (in km/hr) should it travel to arrive exactly on time? 
<pre>Time taken to travel 250 km at 60 km/h: {{{matrix(1,11, 250/60, or, 25/6, or, 4&1/6, "hrs,", or, 4, "hrs,", 10, minutes)}}} 
Since arrival time was 10 minutes later than schedule then to be on time, time should be 4 hrs ({{{matrix(1,4, 4&1/6, hours, - 10, minutes)}}})
We then get the speed it needs to travel to be on-time as: {{{highlight_green(matrix(1,4, 250/4, "=", 62.5, "km/h"))}}}