Answer:
418 4/10
Step-by-step explanation:
To answer this we subtract 450 7/10 from 869 1/10.
We must borrow a '1' from 869 1/10: 868 11/10
Now subtract 450 7/10 from 868 11/10:
418 4/10 (CHANGE IN ELEVATION)
This reduces to 418 2/5.
If all were dimes, the value would be $3.30. Brendan has $2.85 more than that. Each quarter that replaces a dime increases the value by $0.15, so Brendan must have $2.85/$0.15 = 19 quarters.
Brendan has 14 dimes and 19 quarters.
Ok now that i understand the question better i say it is D
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