Indiana Jones has stolen two solid gold bars from a treasure. But now, the village people are behind him. While running away from them, he comes across a bridge formed by a single rope. Now he knows that he can cross the bridge on that rope. But there is a signboard which reads that the rope can carry a maximum weight of 130 pounds only.
Now, the gold bar weighs 20 pounds each and he weighs 100 pounds. How will he cross the bridge now given that he can't leave the gold bar behind and he don't have enough time to return back and take them one by one ?
If you know about the weighing systems, you must be knowing that gold is weighed in Troy system while otherwise normally, the weight is measured using the imperial system.
In Troy system, 12 ounces = 1 pound.
In imperial system, 16 ounces = 1 pound
Thus, 40 pounds of gold weighed in Troy system will be only 30 pounds in the imperial system of weighing. The weight limit for the rope must be in imperial system only as that is the standard weighing system.
Thus the total weight = 100 + 30 = 130 pounds and all he will do is simply walk it carrying both the gold bars.