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
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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