(1)由题意得,销售量=250-10(x-25)=-10x+500,
则w=(x-20)(-10x+500)
=-10x2+700x-10000;
(2)w=-10x2+700x-10000=-10(x-35)2+2250.
∵-10<0,
∴函数图象开口向下,w有最大值,
当x=35时,wmax=2250,
故当单价为35元时,该文具每天的利润最大;
(1)由题意得,销售量=250-10(x-25)=-10x+500,
则w=(x-20)(-10x+500)
=-10x2+700x-10000;
(2)w=-10x2+700x-10000=-10(x-35)2+2250.
∵-10<0,
∴函数图象开口向下,w有最大值,
当x=35时,wmax=2250,
故当单价为35元时,该文具每天的利润最大;