Solve the problem.Robert has built a mechanical model solar system with three balls representing planets at the ends of rods attached to the center representing the sun. The planets are aligned when he turns on the motor. The innermost planet makes a revolution in 18 seconds, the middle planet makes a revolution in 30 seconds, and the outermost planet makes a revolution in 42 seconds. After how many seconds will the planets be aligned again?
A. 1260 seconds
B. 630 seconds
C. 315 seconds
D. 945 seconds
Answer: B
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Given that the pair of triangles is similar, find the unknown length of the side labeled with a variable.
A. 6 B. 18 C. 20 D. 24
Check the given subtraction. If the answer is incorrect, give the correct answer.
71
A. Incorrect; should be 81 B. Incorrect; should be 66 C. Correct D. Incorrect; should be 72
Classify the function as a polynomial function, rational function, or root function, and then find the domain. Write the domain in interval notation.f(t) = t2 + 6
A. polynomial function; [-6, ?) B. polynomial function; (-6, ?) C. polynomial function; (-?, ?) D. polynomial function; (-?, -6) ? (-6, ?)
Solve.The temperature at 5:00 was -4°C. Four hours later, it was -12°C. What was the change in temperature?
A. -16°C B. 16°C C. 8°C D. -8°C