1.

ramu travelled 300 km by train and 200 km by taxi, it took him 5hours 30 minutes. But if he travels 260km by train and 240 km by taxi he takes 6 minutes longer. find the speed of the train and that of the taxi​

Answer»

Explanation:

solution: Let the speed of train is x km/HR

and speed of taxi is y km/hr

Since,Travelling time is given in both the cases,calculate the time taken by train and by taxi and form linear equations

Case1: Abdul travelled 300km by trains and 200km by taxi, it took 5 hours 30 minutes.

Time taken by train to cover 300 km with the speed x km/hr

Time= Distance travelled/speed

= 300/x hr

Time taken by taki to travel 200 km,

= 200/y

\begin{gathered} \frac{300}{x} + \frac{200}{y} = \frac{11}{2} \: \: \: \: eq1\\ \end{gathered}

x

300

+

y

200

=

2

11

eq1

CASE2: Abdul travels 260km by train and 240 km by taxi,he takes 6 minutes longer..

Time taken by train to cover 260 km with the speed x km/hr

Time= Distance travelled/speed

= 260/x hr

Time taken by taki to travel 240 km,

= 240/y

\begin{gathered} \frac{260}{x} + \frac{240}{y} = 5 \: hr \: 36 \: min \\ \\ \frac{260}{x} + \frac{240}{y} = 5 \frac{36}{60} \\ \\ \frac{260}{x} + \frac{240}{y} = 5 \frac{3}{5} \\ \\ \frac{260}{x} + \frac{240}{y} = \frac{28}{5} \: \: \: \: \: eq2 \\ \\ \end{gathered}

x

260

+

y

240

=5hr36min

x

260

+

y

240

=5

60

36

x

260

+

y

240

=5

5

3

x

260

+

y

240

=

5

28

eq2

Eq1 and 2 can be converted to linear equation

\begin{gathered}let \\ \\ \frac{1}{x} = a \\ \\ \frac{1}{y} = b \\ \\ 300a + 200b = \frac{11}{2} \: \: \: \: ...eq3\\ \\ 65a + 60b = \frac{7}{5} \: \: \:... eq4 \\ \\ \end{gathered}

let

x

1

=a

y

1

=b

300a+200b=

2

11

...eq3

65a+60b=

5

7

...eq4

On solving these linear equations by elimination method,

Multiply eq3 by 60 and eq4 by 200 and subtract both

\begin{gathered}60[300a + 200b = \frac{11}{2}]\\\\18000a+12000b=330 \: \: \: \: ...EQ5\\ \\ 200[65a + 60b = \frac{7}{5}]\\\\ 13000a+12000b=280 \: \: \:... eq6\\ \\ \end{gathered}

60[300a+200b=

2

11

]

18000a+12000b=330...eq5

200[65a+60b=

5

7

]

13000a+12000b=280...eq6

Eq5-eq6

\begin{gathered}5000a=50\\\\a=\frac{50}{5000}\\\\a=\frac{1}{100}\\\\\end{gathered}

5000a=50

a=

5000

50

a=

100

1

put the value of a in eq 4

b= 1/80

Now

\begin{gathered}a = \frac{1}{100} \\ \\ b = \frac{1}{80} \\ \\ \end{gathered}

a=

100

1

b=

80

1

Thus,

\begin{gathered} \frac{1}{x} = a \\ \\ \frac{1}{x} = \frac{1}{100} \\ \\ x = 100 \\ \\ \frac{1}{y} = b \\ \\ \frac{1}{y} = \frac{1}{80} \\ \\ y = 80 \\ \\ \end{gathered}

x

1

=a

x

1

=

100

1

x=100

y

1

=b

y

1

=

80

1

y=80

Thus,the speed of train is 100km/hr and speed of taxi is 80 km/hr.

Hope it helps you.



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