As Distance $=$ Speed $\times$ Time if a plane travels 100 x miles in t seconds, its speed is

$\(\frac{100x}{t}\)$ miles $\(/\)$ second $\(=\frac{100x}{t} \times 3600\)$ miles $\(/\)$ hour $\(=\frac{360,000x}{t}\)$ miles $\(/\)$ hour $($ Using 1 hour $=$

3600 seconds $)$

So, the time that the plane would take to travel a distance of $\(y\)$ miles $\(\frac{ Distance } { Speed }=\frac{y}{\frac{360,000 x}{t}}\)$ hours $\(=\frac{y t}{360,000 x}\)$ hours

Hence the answer is (B).