CTET 2 Math and Science Feb 2014 Paper

Question : 77 of 120

Marks: +1, -0

The odometer reading of a moving car at 8:00 a.m. is 36540 km and at 10:00 a.m. 36666 km. If the car is moving on a zigzag path with variable speeds, its average speed in metres per second is

6.3
12.6
17.5
35

Validate

Solution:

Distance covered

=36666–36540=126km=126000

m Time elapsed

=10:00am–8am=2\hours=720\sec

=\;\;{126000}/{7200}=17.5{m}/{s}

Alternate method:
The reading is 8 o’ clock = 36540 km
The reading at 10 o’ clock = 36666 km
The distance travelled in 2 hours

∴=(36666-36540){km}=126{km}

∴\text "Average Speed"=\;\;{\;\text"Distance"\;}/{\;\text"Time"\;}=\;\;{126}/{2}{km}/{hr}

=\;\;{126}/{2}×\;\;{5}/{18}{m}/{sec}=\;\;{35}/{2}{m}/{sec}=17.5{m}/{sec}

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