A person participates in a weekly office pool in which he has one chance in ten of winning the prize. If he participates for 5 weeks in succession, what is the probability of winning at least one prize.

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?