I walk a certain distance and ride back taking a total time of 37 minutes. I could walk both ways in 55 minutes. How long would it take me to ride both ways ?
19
This problem is a classic example of solving time and distance scenarios using simple algebraic equations. We are given information about the time taken for a journey involving walking and riding, and we need to find the time taken to complete the journey solely by riding.
Let's define the variables for the problem:
We are given two pieces of information, which we can translate into equations:
Scenario 1: Walk a distance and ride back.
The total time taken to walk the distance $d$ and ride back the distance $d$ is 37 minutes.
This gives us our first equation:
$$t_w + t_r = 37 \quad \text{(Equation 1)}$$
Scenario 2: Walk both ways.
The total time taken to walk both ways (distance $d$ and back distance $d$) is 55 minutes.
Walking both ways covers a total distance of $2d$. The time taken to walk distance $d$ is $t_w$, so walking $2d$ takes $2 \times t_w$.
This gives us our second equation:
$$2t_w = 55 \quad \text{(Equation 2)}$$
We can use Equation 2 to find the time taken to walk the distance $d$ ($t_w$).
$$2t_w = 55$$
Divide both sides by 2:
$$t_w = \frac{55}{2}$$
$$t_w = 27.5 \text{ minutes}$$
So, it takes 27.5 minutes to walk the certain distance.
Now that we have the value of $t_w$, we can substitute it into Equation 1 to find the time taken to ride the distance $d$ ($t_r$).
$$t_w + t_r = 37$$
Substitute $t_w = 27.5$:
$$27.5 + t_r = 37$$
Subtract 27.5 from both sides:
$$t_r = 37 - 27.5$$
$$t_r = 9.5 \text{ minutes}$$
So, it takes 9.5 minutes to ride the certain distance.
The question asks how long it would take to ride both ways. Riding both ways covers a total distance of $2d$. Since it takes $t_r$ minutes to ride distance $d$, it will take $2 \times t_r$ minutes to ride $2d$.
Time to ride both ways $= 2t_r$
Substitute the value of $t_r = 9.5$ minutes:
$$2t_r = 2 \times 9.5$$
$$2t_r = 19 \text{ minutes}$$
Therefore, it would take 19 minutes to ride both ways.
| Journey Segment | Time Taken |
|---|---|
| Walk certain distance ($t_w$) | 27.5 minutes |
| Ride certain distance ($t_r$) | 9.5 minutes |
| Walk both ways ($2t_w$) | 55 minutes (Given) |
| Ride both ways ($2t_r$) | 19 minutes (Calculated) |
| Walk + Ride ($t_w + t_r$) | 37 minutes (Given) |
The time taken to ride both ways is 19 minutes.
| Concept | Explanation |
|---|---|
| Algebraic Modelling | Representing unknown quantities (time) with variables ($t_w, t_r$) and forming equations from given information. |
| Solving Linear Equations | Using substitution or elimination to find the values of the unknown variables from the system of equations. |
| Interpreting the Question | Carefully understanding what 'walk both ways' and 'ride both ways' mean in terms of distance covered and time taken. |
This problem is related to the fundamental concepts of time, speed, and distance. The basic relationship is:
$$\text{Distance} = \text{Speed} \times \text{Time}$$
From this, we can derive:
$$\text{Time} = \frac{\text{Distance}}{\text{Speed}}$$
$$\text{Speed} = \frac{\text{Distance}}{\text{Time}}$$
In this problem, we didn't explicitly use speed, but we assumed that the walking speed is constant and the riding speed is constant. If $v_w$ is the walking speed and $v_r$ is the riding speed over distance $d$, then:
The given equations can also be thought of in terms of speed:
From the second equation, $\frac{d}{v_w} = \frac{55}{2} = 27.5$. This is exactly our $t_w$. Substituting this into the first equation gives $27.5 + \frac{d}{v_r} = 37$, which means $\frac{d}{v_r} = 37 - 27.5 = 9.5$. This is our $t_r$. We needed to find $\frac{2d}{v_r}$, which is $2 \times \frac{d}{v_r} = 2 \times 9.5 = 19$ minutes. This confirms our approach using just time variables was correct and simpler for this specific problem structure.
A train having length 210 metres takes 25 seconds to cross a 540 metres long bridge. How much time will the train take to cross a 630 metres long bridge?
A person X from a place A and another person Y from a place B set out at the same time to walk towards each other. The places are separated by a distance of 15 km. X walks with a uniform speed of 1.5 km / hr and Y walks with a uniform speed of 1 km / hr in the first hour, with a uniform speed of 1.25 km / hr in the second hour and with a uniform speed of 1.5 km / hr in the third hour and so on.
Which of the following is / are correct?
1. They take 5 hours to meet.
2. They meet midway between A and B.
Select the correct answer using the code given below:
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