If a down jacket is sold at 50% off the price, it will earn 50 yuan, and if it is sold at 60% off the price, it will earn 80 yuan 1. What is the price and cost of each down jacket? In order to ensure the profit is not less than 20 yuan, how much discount at most? (solved by linear equation of one variable)

If a down jacket is sold at 50% off the price, it will earn 50 yuan, and if it is sold at 60% off the price, it will earn 80 yuan 1. What is the price and cost of each down jacket? In order to ensure the profit is not less than 20 yuan, how much discount at most? (solved by linear equation of one variable)

1. Set the price as X Yuan
X*0.5-50=X*0.6-80
0.1X=30
X=300
Cost = 300 * 0.5-50 = 100
The price and cost of each down jacket are 300 yuan and 100 yuan respectively
2. Set a maximum discount of Y
300*Y=100+20
300Y=120
Y=0.4
40% off at most