Trains Boats and Streams Practice Test 3 with solutions

Let length of the two trains be x m and $\frac{140\mathit{x}\mathit{x}}{100}-\frac{7\mathit{x}}{5}$ m,
then $\mathit{x}+\frac{7\mathit{x}}{5}$ = $72\times \frac{5}{18}\times 30$
⇒ $\frac{12\mathit{x}}{5}$ = 600
∴ x = $\frac{5\times 600}{12}$ = 250 m
Length of another train = $\frac{7\mathit{x}}{5}$ = $\frac{7}{5}$ × 250 = 350 m
Hence, difference between the lengths = 350 – 250 = 100 m