5
In a computer game, there are builders and destroyers. Together there are 20 of them.
Some of them try to build a wall around a castle while the rest try to demolish it. Each of
the builders can build the wall alone m 15 hours while any of the destroyers can demolish
it in 10 hours. If all 20 builders and destroyers are made active when there is no wall and
the wall gets built m 3 hours, how many of them are destroyers ?
Some of them try to build a wall around a castle while the rest try to demolish it. Each of
the builders can build the wall alone m 15 hours while any of the destroyers can demolish
it in 10 hours. If all 20 builders and destroyers are made active when there is no wall and
the wall gets built m 3 hours, how many of them are destroyers ?
- A6
- B7
- C8
- D5
Answer not set