问2题题目 ，第一次发帖，不好意思

louchao5678

第一次发帖 ，图片也不知道怎么上  我有2题数学不会做 我打上来吧

louchao5678

in the certain conference room each room have the same of chairs ,and  the number of row is 1 less than the number of the chairs in a row ,how many chairs are in a row?
1,  there is a total of 72 chairs
2,after 1 is removed from the last row,there is the total of  17 chairs in the last  2 rows

louchao5678

andy's  take home pay was the same last each month,and she saved the same fraction of  her take home each month. the total amount of money she saved at the end year was 3 times amount of that portioin of her monthly take home pay that she did not save. if  all the money that she saved last year was form her take home pay,what fraction of her take home pay did she save each month？
1/2    1/3  1/4  1/5  1/6

hot_heart

in the certain conference room each room have the same of chairs ,and  the number of row is 1 less than the number of the chairs in a row ,how many chairs are in a row?
1,  there is a total of 72 chairs
2,after 1 is removed from the last row,there is the total of  17 chairs in the last  2 rows

答：我 认为1与2都独立充分
原因：条件1：可以设row=r   每排的数量则为r+1    所以总的chairs=r*(r+1)
       根据条件r*(r+1)=72     r=8       充分
条件2：列式为：2*（r+1）=17+1   得 r=8   所以也是充分的

louchao5678

怎么是这样做的啊。。。。我题目啊 看不懂啊。。。