MATH
posted by TINA on .
FOUR CYCLISTS A,B,C&D WANTS TO CROSS A BRIDGE BUT DUE TO BAD CONDITION OF BRIDGE ONLY TWO AT A TIME CAN CROSS IT. IF A TAKES 1 MINUTES, B TAKES 2 MINUTES,C TAKES FIVE MINUTES & D TAKES 10 MINUTES TO CROSS THE BRIDGE, HOW THEY ALL CAN CROSS THE BRIDGE IN 17 MINUTES. IF ONE LAMP IS AVAILABLE TO CROSS THE BRIDGE.

 A & B cross the bridge (2 minutes)
 A go back with the lamp (1 minute)
 C & D cross the bridge with lamp (10 minutes)
 B go back with the lamp (2 minutes)
 A & B cross the bridge with lamp(2 minutes