The rate at which a body cools also depends on its exposed surface area S. If S is a constant, then a modification of (2), given in Section 3.1, is dT dt = KS(T - Tm), where k < 0 and Tm is a constant. Suppose that two cups A and B are filled with coffee at the same time. Initially, the temperature of the coffee is 65° C. The exposed surface area of the coffee in cup B is twice the surface area of the coffee in cup A. After 30 min the temperature of the coffee in cup A is 37° C. If Tm = 20° C, then what is the temperature of the coffee in cup B after 30 min? (Round your answer to two decimal places.)

9. 6100 + 318 8 8

Section 1 (Computation) 1. 2. 3. (1.95 0.959) + (0.4)² (28.6+1.85)-(0.19)² 4. 5. What is 18% of 320 6. Express 15 as a percentage of 9 Section 2 (Simplifying algebraic expressions) 1. 16y +24x + 7y + 17x 2. 25a + 19b - 16a+ 12b. 3. 43m² +51n²-27n²-35m² 4. 3r-5s-11r + 4s. 5. 12a x 7b 6. 16m x 14n 7. 11j¹x 16j² 8. 9e x 13e 9. 108y + 12y² 10. (6a7x 8a³) + 16a

8 9. 10 Help? Read It 2/9 3/4