the defense department has seven different contracts that de

the defense department has seven different contracts that deal with a high-security project. Four companies can manufacture the distinct parts called for in each contract, and in order to maximie the security of the overall project, it is best to have all four companies working on some part. In how many ways can the contracts be awarded so that every company is involved?

Solution

Number of ways=selection of 4 companies for all the seven contract

All company will get all the part of the contract

thus number of ways contract can be awarded =7*7*7*7=7^4   ways