Difference means subtract, so we use subtraction:
*first we need to make the fractions have the same denominator
1/4 = 3/12
2/3 = 8/12
126(3/12) - 78(8/12)
*since the fraction in the first term is smaller than the second, make it improper
125(15/12) - 78(8/12)
now simply subtract:
125 - 78
= 47
15 - 8
= 7
* this is now (7/12)
now put them back together:
47(7/12)
That's the final answer!
The best way to solve this is by giving a visual idea of the glass ornaments. so We will have letter G represent Green, O for Orange, B for Brown, P for Purple.
Sample 1:G,O,B,P
Sample 2:G,P,O,B
Sample 3:P,G,O,B
Sample 4:O,G,P,B
Sample 5:G,O,P,B
This is what you can do this should be the right amount of ways to arrange them.

Step-by-step explanation:








profit=f(x)
so solve for f(x)=1000
1000=70n-400
add 400 to both sides
1400=70n
divide both sides by 70
20=n
20 students need to be enrolled to make a profit of 1000.00