Peter's age is X years in the year x squared.
Which of these is the year of his birth?
(a) 1963
(b) 1980
(c) 1990
(d) 2025
评论
This question means peters age squared equals the year of which he was born in. For example: if I was 12, the year I would be born in is 144. If someone was 10, the year they would be born is 100. Peters age x peters age = year he was born in.
This is what I think. Peters age should be 45, as 45 x 45= 2025. BUT, 2025 is right now, to find out the year of which he was born in, we'd have to minus 45 (his age) and the final answer is 1980.
评论
这是几年级的数学啊？
评论
Thanks very much. It's grade 6.
评论
His age is 45.
Number with last digit as 3 cannot be a squared number, 1980, 1990 is not squared number either.
45*45=2025
2025-45=1980
[ 本帖最后由 wo-ai-wo-jia 于 2012-3-20 10:04 编辑 ]
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