35
“Negative times a negative is a positive”
Sixth grade
Because if you divide their total profit by the total amount of hours they worked, you would find that the sixth grade's income per hour is the highest.
Sixth grade: 170÷5=34
Seven grade: 112÷4=28
Eighth grade: 192÷6=32
Answer:
total bill=1644
let he drives x kilometer
then
500*2+8*x=1644
1000+8x=1644
8x= 1644-1000
8x= 644
x= 644/8=80.5 km
Step-by-step explanation:
A pharmacist has 40% and 80% of iodine solutions on hand. How many liters of each iodine solution will be required to produce 4 liters of a 50% iodine mixture?
.
Let x = liters of 40% iodine
then
4-x = liters of 80% iodine
Using algebra:
.40x + .80(4-x) = .50(4)
.40x + 3.20-.80x = 2
3.20-.40x = 2
x = 4 liters (40% iodine)
80% iodine:
4-x = 4-4 = 0 liters needed (80% iodine)