A shopkeeper earns a profit of 5 by selling one pen and incurs a loss pf 1 per pencil while selling pencils of her old stock
(a) in a particular month she earns a profit of 30. in this period, she sold 10
she sold 10 pens how many pencils did she sell in this period?
(b)in the next month she earns neither profit nor loss.ifshe sold
how many pencils did she sell?