Sagot :
Step-by-step explanation:
hope it help
correct me if i wrong

Answer:
when oven sells 20 then fan must be sell 28.
Step-by-step explanation:
let number of oven sells are x and number of fan sells are y
then,
80 x 50y = 3000
when
x=20
80x + 20+ 50y= 3000
1600 + 50y = 3000
50y=1400
y= 1450/50
y=28