Correct Answer: C

Rationale: To multiply 25 by 4, you get 100. To express the result in decimal form, you divide by 100. Therefore, the result is 1. Choice A (0.01) is incorrect as it represents 1/100, not the result of 25 4. Choice B (0.1) is incorrect as it represents 1/10. Choice D (10) is incorrect as it is the result before converting it to decimal form.

Correct Answer: A

Rationale: To determine the initial amount she had, we subtract the amount spent ($18) from the total amount she had after spending. If she had $1,070 after spending, subtracting $18 gives us $1,052, which was the initial amount. Choices B, C, and D are incorrect as they do not consider the subtraction of the amount spent to find the initial amount.

Correct Answer: A

Rationale: Military time uses a 24-hour clock format where the hours range from 00 to 23. In this format, 6:30 A.M. is expressed as 0630. Choice B (6030) and Choice C (1503) are incorrect as they do not follow the 24-hour clock format. Choice D (1530) represents 3:30 P.M., not 6:30 A.M.

Correct Answer: B

Rationale: To determine the tip percentage left, divide the tip amount ($36) by the total bill amount ($200), then multiply the result by 100 to express it as a percentage: (36/200) x 100 = 18%. Therefore, he left an 18% tip on the total bill amount. Choice A (16%) is incorrect because the correct calculation results in 18%. Choice C (20%) and Choice D (22%) are incorrect as they do not match the calculated percentage based on the provided numbers.

Correct Answer: A

Rationale: The Mayan numeric system was a base 20 system, known as vigesimal, as it used base 20 numerals. This system was unique and employed a combination of symbols and positional notation to represent numbers. The Babylonian system was a base 60 system, Roman numerals were based on combinations of letters, and Arabic numerals are in base 10, making choices B, C, and D incorrect.