一到英文数学题
问题描述：
一到英文数学题
Mary’s height increased by 20% between her 5th birthday and her 10th birthday.It increased by 15% between her 10th birthday and her 15th birthday,and it increased by 10% between her 15th birthday and her 20th birthday.By how much did her height increase between her 5th birthday and her 20th birthday?
答
设mary 5岁时体重为1,
那么她十岁时,体重为：1*（1+20%）=1.2,
她15岁时,体重为：1.2*（1+15%）=1.38,
她20岁时,体重为：1.38*（1+10%）=1.518,
所以她20岁时比5岁时,体重增加了,51.8%