The task is to generate the correct answer for a given math problem.

[EX Q]: Problem: there are 7 executives , including the ceo and cfo , that are asked to form a small team of 4 members . however , the ceo and cfo may not both be assigned to the team . given this constraint , how many ways are there to form the team ?
[EX A]: 25

[EX Q]: Problem: how much interest will $ 10,000 earn in 9 months at an annual rate of 4 % ?
[EX A]: $ 300

[EX Q]: Problem: a can do a work in 15 days and b in 20 days . if they work on it together for 7 days , then the fraction of the work that is left is
[EX A]:
11 / 6