A person travels 444 km by train, 260 km by bike and 112 km by auto. It took a total of 15 hours. If the speed of the train is 3 times the speed of an auto and \(1\frac12\) times the speed of bike, then the speed of the bike, in kmph, is
Show Hint
When multiple speed relations are given, express all speeds in terms of one variable first.
Concept:
Use the relation:
\[
\text{Time}=\frac{\text{Distance}}{\text{Speed}}
\]
Step 1: Assume bike speed.
Let bike speed be:
\[
x \text{ kmph}
\]
Given:
Train speed is \(1\frac12\) times bike speed.
\[
=\frac32x
\]
Train speed is also \(3\) times auto speed.
So auto speed:
\[
=\frac{\frac32x}{3}
\]
\[
=\frac x2
\]
Step 2: Write time for each journey.
Train:
\[
\frac{444}{\frac32x}=\frac{296}{x}
\]
Bike:
\[
\frac{260}{x}
\]
Auto:
\[
\frac{112}{x/2}=\frac{224}{x}
\]
Step 3: Use total time.
\[
\frac{296}{x}+\frac{260}{x}+\frac{224}{x}=15
\]
\[
\frac{780}{x}=15
\]
Step 4: Solve for \(x\).
\[
x=\frac{780}{15}
\]
\[
x=52
\]
Thus, the speed of the bike is:
\[
\boxed{52 \text{ kmph}}
\]