# Shreya goes to her college from home at a speed of 60 km/h and reaches 12 min late. If she goes at a speed of 70 km/h she reaches 8 min before the sch

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Shreya goes to her college from home at a speed of 60 km/h and reaches 12 min late. If she goes at a speed of 70 km/h she reaches 8 min before the scheduled time. How far is her college from home?
1. 140 km
2. 100 km
3. 150 km
4. 160 km

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Correct Answer - Option 1 : 140 km

GIVEN:

Speed when 12 min late = 60 km/h

Speed when 8 min early = 70 km/h

FORMULA USED:

Speed = Distance/Time

CALCULATION:

Let the distance be x km.

Time taken at 60 km/h = x/60 × 60 = x minutes

Time taken at 70 km/h = x/70 × 60 = 6x/7 minutes

A.T.Q

x - 12 = 6x/7 + 8

7x - 84 = 6x + 56

x = 140 km

∴ The distance is 140 km

ALTERNATE SOLUTION:
Distance = [(speed1 × speed2)/Difference in speeds] × time saved

Time saved = 12 + 8 = 20 min =1/3 hr

∴ D = [(60 × 70)/10] ×  1/3

D = 140 km

∴ The distance is 140 km