Question 1162390
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The solution by the other tutor is fine....<br>
If you set up the problem a bit differently, it is easy to solve without formal algebra, using basic arithmetic.<br>
The ratio of the speeds is x-30:x; the ratio of distances is 140:210.<br>
{{{(x-30)/x = 140/210}}}<br>
Simplify the fraction on the right:
{{{(x-30)/x = 2/3}}}<br>
Now multiply numerator and denominator on the right by some number so that the difference between the numerator and denominator is 30 (as the expression on the left requires).  Since the current difference between the numerator and denominator is 1, the number to multiply is 30:<br>
{{{(x-30)/x = 60/90}}}<br>
The speeds of the two trains are 60mph and 90mph.<br>