A student travels from his house to school at 10 km/hr and reaches school 2 hours late. The next day he travels 15 km/hr and reaches school 1 hour early. What is the distance between his house and the school?  Choose the correct choice from the following options.
A) 60	B) 70	C) 80	D) 90	E) 100
Let x be the distance from his house to the school.   x/10 = x/15 + 3   6x = 4x + 180   2x = 180   x = 90 km   The answer is 90.
<result>D</result>
A student travels from his house to school at 10 km/hr and reaches school 2 hours late. The next day he travels 15 km/hr and reaches school 1 hour early. What is the distance between his house and the school?