In both cases,

(as a consequence of the interesecting secant-tangent theorem)
So we have
10.





(omit the negative solution because that would make at least one of AB or AD have negative length)
11.




(again, omit the solutions that would give a negative length for either AB or AD)
No because 2/5 equals 4/10, which is .4, not .25 :)
18 min per pound
324 min. = X
______ _____
18 1 pound
324 x 1 = 324 324/18= 18 pounds
Cross multiply then divide as above.
30,000(1.067)^5
Punch that in a scientific calculator and you should get the answer.