Answer:
He lost 147.35 marks
Step-by-step explanation:
Take the total marks and subtract the marks he got to find the marks he lost
600-452.65= 147.35
21 chaperones are needed for 420 students.
Step-by-step explanation:
No. of juniors = 148
No. of seniors = 272
Total = 148+272 = 420 students
3 chaperones = 60 students
1 chaperone = 
Ratio of chaperon to students = 1:20
Let,
x be the number of chaperons for 420 students.
Ration of chaperones to students = x:420
Using proportion
Ratio of chaperones to students :: Ratio of chaperons to students

Product of mean = Product of extreme

Dividing both sides by 20

21 chaperones are needed for 420 students.
Keywords: ratio, proportion
Learn more about ratios at:
#LearnwithBrainly
-6x-13y
2x+(3x2)-14x+(3x2)+12x+(3x2)-12x+(3x2)-12x+(3x2)-12x
2x+6x-14x+6x+12x+6x-12x+6x-12x+6x-12x=-6
-6y+7y+1y-1y+1y-13y=-13y
if a letter is by itself then there is automatically a one in front of it