/kloc-how much can I sell 0/00 pens?

100 all sold according to 6 yuan, and the profit: (6 yuan -4 yuan) x 100=200 yuan.

Actual profit: 188 yuan.

100 has less profit: 200 yuan-188 yuan = 12 yuan (that is, the profit of discounted pens).

Less profit per transaction after discount: 6 yuan (1-x0.9)=0.6 yuan.

Number of pens with 10% discount: 12 yuan /0.6 yuan =20 (sticks)

Solution 2, Algebraic Method

There are m pens with a 10% discount.

10% off sales profit: (0.9*6-4)m

6 yuan sales profit: (6-4)*( 100-m)

* * * Profit 188 yuan.

Column equation: (0.9 * 6-4) m+(6-4) * (100-m) =188.

Solution: m=20 branches

There are 20 pens with a 10% discount.