If the White Rock Fire Department invests now in new ladder systems for several of its trucks, the department would save $3500 every 6 months in repair costs. What single cash investment made now is equivalent to the repair payments if interest is 8% compounded quarterly and the payments are made
(a) At the end of every 6 months for 15 years?
(b) At the beginning of every 6 months for 10 years?
(c) At the end of every 6 months for 8 years but deferred for 4 years?
(d) At the beginning of every 6 months for 9 years but deferred for 3 years?
(e) At the end of every 6 months in perpetuity?
(f) At the beginning of every 6 months in perpetuity?