College Mathematics
answers to
linear growth vs. exponential growth


1.
   (a) linear		[ plus    19    ]
   (b) linear		[ plus     7    ]
   (c) exponential	[ times    5    ]
   (d) linear		[ plus   170    ]
   (e) exponential	[ times    1.08 ]
   (f) linear		[ plus  8000    ]
   (g) exponential	[ times    3    ]

2.
   (a) C = 32 + 6T
   (b) 326 cents, or $3.26
   (c) Cyndi must talk less than 11 minutes and 10 seconds.
       If Cyndi is billed by the minute, she can talk up to 11 minutes.

3.
   (a) C = 1.77 + 0.04(T - 30), or
       C = 0.57 + 0.04T
   (b) 237 cents, or $2.37
   (c) Dana must talk less than 235 minutes and 45 seconds.
       If Dana is billed by the minute, she can talk up to 235 minutes.

4.
   (a) 43,000
   (b) 29,851

5.
   (a) $22.10 per hour [ $6.80+(1.7 )x9 ]
   (b) $50.66 per hour [ $6.80x(1.25)^9 ]