Bunuel
At 10:00 p.m., a cyclist is 10 miles from home on a straight road. From that time on, the cyclist continues riding farther from home at a constant speed of 3 minutes per mile, then turns around and rides back toward home at the same speed along the same road. If the cyclist must arrive back home at 10:48 p.m., how many additional miles can the cyclist travel away from home after 10:00 p.m. before turning around?
A. 2
B. 3
C. 6
D. 9
E. 12
Let us consider a line segment AB, where A denotes the home , and B denotes the Cyclist.
The distance AB is 10 miles at 10.00 pm.
The Cyclist rides at the same speed of 1 mile per 3 minutes.
The cyclist rides away from the home, and then turns back towards home. The cyclist reaches Home at 10:48 pm.
The distance the cyclist travels after 10:00 pm in the
forward direction is
d miles.
The distance the cyclist travels in the
backward direction is :
10+d miles.
Total distance travelled after 10 pm = d + 10 + d =
10 + 2d miles.
Speed of cyclist is 1 mile per 3 mins.
By UNITARY METHOD : So, in 48 mins, the distance travelled is 48/3 miles =
16 miles. 10 + 2d = 16
2d = 6
d =3 miles. The distance the cyclist travels after 10:00 pm before turning back = 3 miles.
Option B