設(shè)10個數(shù):195.5,196.5,197.5,198.5,199.5,200,200.5,201,201.5,202.5的平均數(shù)為A,則10A=
1993
1993
分析:經(jīng)觀察,這10個數(shù)都與200相近,把每個數(shù)減200所得的差,分別記作-4.5,-3.5,-2.5,-1.5,-0.5,0,+0.5,+1,+1.5,+2.5,上述這10個差數(shù)的平均數(shù)為-0.7,A=199.3,所以10A=1993.
解答:解:∵195.5,196.5,197.5,198.5,199.5,200,200.5,201,201.5,202.5與200分別相差
-4.5,-3.5,-2.5,-1.5,-0.5,0,+0.5,+1,+1.5,+2.5,
∵[(-4.5)+(-3.5)+(-2.5)+(-1.5)+(-0.5)+0+0.5+1+1.5+2.5]÷10=-0.7,
∴A=200-0.7=199.3,
則10A=1993.
故答案為:1993.
點評:本題考查的是平均數(shù)的性質(zhì).把與200相差的數(shù)加起來除以10再加上200可以簡便計算.
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