SATMathematics Practice Test 1

Substituting 1,000 for a in the equation a=1,052+1.08t gives 1,000=1,052+1.08t,and thus t=

−52

1.08

≈−48.15. Of the choices given,48°F is closest to −48.15°F.
Since the equation a=1,052+1.08t is linear, it follows that of the choices given, −48°F is the air temperature when the speed of a sound wave is closest to 1,000 feet per second.
Choices A, C, and D are incorrect, and might arise from errors in calculating

−52

1.08

or in rounding the result to the nearest integer.
For example, choice C could be the result of rounding −48.15 to −49 instead of −48.