Mathematical Process Standards>Using a Problem-Solving Model to Solve and Justify Solutions(TEKS.2A.9-12.1.B) Practice Test

Set $A=70$ for the ambient temperature, define $B$ and $r$, and write equations from $T(5)=140$ and $T(10)=120$ to form a system to solve.

Assume a linear model $T(t)=mt+b$ because the temperatures are decreasing.

Guess $r=0.5$ since the temperature is dropping and compute $T(15)$.

Immediately average 140 and 120 to estimate $T(15)$ without solving for $B$ and $r$.