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5.What is the number of integers that are comm on to both set S and set T? (1)The number of integers in S is 7, and the number of integers in Tis 6. (2)U is the set of integers that are in S only or in T only or in both, and the number of integers in U is 10.
26.Merle's spare change jar has exactly 16 U.S. coins,each of which is a 1-cent coin,a 5-cent coin,a 10-cent coin,a 25-cent coin or a 50-cent coin. If the total value of the coins in the jar is 288 U.S. cents, how many 1-cent coins are in the jar? (1)The exact numbers of 10-cent, 25-cent, and 50-cent coins among the 16 coins in the jar are, respectively, 6, 5, and 2. (2)Among the 16 coins in the jar there are twice as many 10-cent coins as 1-cent coins.
52.The top surface area of a square table top was changed so that one of the dimensions was reduced by 1 inch and the other dimension was increased by 2 inches. What was the surface area before these changes were made? (1)After the changes were made, the surface area was 70 square inches. (2)There was a 25 percent increase in one of the dimensions.
63.If x is a positive integer, how many positive integers less than x are divisors of x? (1)x平方 is divisible by exactly 4 positive integers less than x平方 (2)2x is divisible by exactly 3 positive integers less than 2x.
70.Given a positive number N, when N is rounded by a certain method (for convenience, call it Method Y), the result is 10n if and only if n is an integer and 5*10的n-1次方 ≤N<5∗10的n次方 .In a certain gas sample, there are, when rounded by Method Y, 10的21次方 molecules of H2 and also10的22次方 molecules of O2. When rounded by Method Y. what is the combined number of H2 and O2 molecules in the gas sample? (1) The number of H2 molecules and the number of O2 molecules are each less than 3*10的21次方 (2) The number of H2 molecules is more than twice the number of O2 molecules
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发表于 2019-10-26 11:00:20
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