3. lynne is tiling her long and narrow rectangular front hall. the hall is 2 tiles wide and 8 tiles long. she is going to use exactly 6 black tiles and exactly 10 white tiles. what is the number of distinct ways of tiling the hall so that no two black tiles are adjacent? 4. how many ways are there of choosing 8 calculators from 12 (distinguishable) calculators?

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?

Which of the following circles have their centers on the x-axis? check all that apply.

Find the length of the normal and the angle it makes with the positive x-axis. (see pictured below)