Correct Answer - Option 4 : 4.2 km
Given:
Speed 1 = 3.5 km/hr reaches 6 min late
Speed 2 = 4.5 km/h reaches 10 min early.
Formula used:
Distance = [(Speed 1 × Speed 2)/(Difference of Speeds)] × time difference
Calculation:
Distance = [(Speed 1 × Speed 2)/(Difference of Speeds)] × time difference
⇒ Distance = [(3.5 × 4.5)/1] × 16/60
⇒ 4.2 km
∴ The distance between her house and the school is 4.2 km.
Mistakes Point:
Convert all given data in same units i.e all-time in an hour or sec and distance in Km or meter according to requirements.