What is the present worth of these future payments? (a) $5,500 6 years from now at 10% compounded annually (b) $8,000 15 years from now at 6% compounded annually (c) $30,000 5 years from now at 8%...

(a) $5,500 6 years from now at 10% compounded annually

(b) $8,000 15 years from now at 6% compounded annually

(c) $30,000 5 years from now at 8% compounded annually

(d) $15,000 8 years from now at 12% compounded annually