1,2,3,4,5,6,7how many pairs of different numbers can be chosen from the list above so that the sum of the two numbers is even?(note:the pair 1,3 is the same as the pair 3,1)第二题square tiles measuring 1/2 foot by 1/2 foot are sold in boxes contai
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![1,2,3,4,5,6,7how many pairs of different numbers can be chosen from the list above so that the sum of the two numbers is even?(note:the pair 1,3 is the same as the pair 3,1)第二题square tiles measuring 1/2 foot by 1/2 foot are sold in boxes contai](/uploads/image/z/3454115-59-5.jpg?t=1%2C2%2C3%2C4%2C5%2C6%2C7how+many+pairs+of+different+numbers+can+be+chosen+from+the+list+above+so+that+the+sum+of+the+two+numbers+is+even%3F%28note%3Athe+pair+1%2C3+is+the+same+as+the+pair+3%2C1%29%E7%AC%AC%E4%BA%8C%E9%A2%98square+tiles+measuring+1%2F2+foot+by+1%2F2+foot+are+sold+in+boxes+contai)
1,2,3,4,5,6,7how many pairs of different numbers can be chosen from the list above so that the sum of the two numbers is even?(note:the pair 1,3 is the same as the pair 3,1)第二题square tiles measuring 1/2 foot by 1/2 foot are sold in boxes contai
1,2,3,4,5,6,7
how many pairs of different numbers can be chosen from the list above so that the sum of the two numbers is even?(note:the pair 1,3 is the same as the pair 3,1)
第二题
square tiles measuring 1/2 foot by 1/2 foot are sold in boxes containing 10 tiles each.what is the least number of the boxes of tiles needed to cover a rectangular floor that has dimensions 12 feet by 13 feet?
这道真心没看懂= =
1,2,3,4,5,6,7how many pairs of different numbers can be chosen from the list above so that the sum of the two numbers is even?(note:the pair 1,3 is the same as the pair 3,1)第二题square tiles measuring 1/2 foot by 1/2 foot are sold in boxes contai
1.
Grp A (0dd numbers):1,3,5,7
Grp B (Even numbers):2,4,6
U can choose 2 both from Grp A or from Grp B,totally:
C(2,4)+C(2,3)=9
2.
12×13÷(1/2×1/2×10)=62.4≈63
three pairs
1.1,3 1,5 1,7 2,4 2,6 3,5 3,7 4,6 5,7 共9对
2.我翻译的通俗点,就是 1/2*1/2规格的正方形瓷砖一盒能装10块,那么用这种瓷砖铺完规格12*13的地板至少需要几盒? 12×13÷(1/2×1/2×10)=62.4≈63 盒
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1.1,3 1,5 1,7 2,4 2,6 3,5 3,7 4,6 5,7 共9对
2.我翻译的通俗点,就是 1/2*1/2规格的正方形瓷砖一盒能装10块,那么用这种瓷砖铺完规格12*13的地板至少需要几盒? 12×13÷(1/2×1/2×10)=62.4≈63 盒
O(∩_∩)O
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