Quant Memo
Brainteasers/●●●●

Beat the dying torch across the bridge

Asked at IMC

Four friends must cross a bridge at night sharing a single torch. The bridge holds at most two people at once, the torch must travel with every crossing, and a pair crosses at the slower person's pace. Their solo times are 2, 4, 7, and 10 minutes.

Here is the catch: the torch's battery has only 25 minutes of light left, and once it dies on the bridge, anyone still crossing is stranded.

Can all four reach the far side before the torch dies? If so, give a schedule.

Your answer

More Brainteasers questions