[ Text problems (miscellaneous). ] [ Systems of linear equations ]

A calf weighs as much as a kid together with a piglet. And a piglet together with a calf weighs as much as a lamb together with a kid.

How much does the piglet weigh, if the lamb weighs 30 kg?
A lamb and a kid weigh as much as a kid and two piglets. Therefore, a piglet weighs half as much as a lamb.

## Answer

15 kg.