Question

On a certain project the only grades awarded were

75 and 100. If 85 students completed the project

and the average of their grades was 85, how many

earned 100?

Answer 1

tips, yummy?

Answer 2

lol

Answer 3

hello patrick

Answer 4

x=# of students who got 75
y=# of students who got 100

x+y=85

that much we know

Answer 5

x+y=85

Answer 6

and

75x+100y=85

Answer 7

so just solve for y :)

Answer 8

k

Answer 9

x+y=85
75x+100y=85
solve for y

Answer 10

100y=85-75x

Answer 11

y=17/20-3/4x

Answer 12

y=7

Answer 13

x=78?

Answer 14

so seven people go hundreds?

Answer 15

nope

Answer 16

x=78

Answer 17

y=7

Answer 18

those values are correct, right?

Answer 19

nope :\
that would make the average 77 or 78, not 85

Answer 20

im kinda confused myself now

Answer 21

yummu

Answer 22

lol wat?

Answer 23

t carrol is coming

Answer 24

@jim_thompson5910 or @Hero

Answer 25

tips carrol?

Answer 26

85 = N(75) + (85-N)(100). So, 85-N got a 100.

Answer 27

Just solve for N and hence, 85-N.

Answer 28

N=336.6?

Answer 29

wah?

Answer 30

yummydum's first equation is correct

Answer 31

the second equation is missing something

Answer 32

75x+100y represents the sum of all the scores, you need to divide that sum by 85 since there are 85 scores

Answer 33

x+y=85

Answer 34

so the second equation should be

(75x+100y)/85 = 85

Answer 35

(75x+100y)/85=85

Answer 36

yes

Answer 37

solve for y?

Answer 38

yes, y = # of people who got 100

Answer 39

y==71.5

Answer 40

y=71.4

Answer 41

y=71.5

Answer 42

no, you should get a whole number

Answer 43

ahh

Answer 44

75x+100y=85 squared?

Answer 45

good

Answer 46

keep going

Answer 47

y=72.25-3xy?

Answer 48

no

Answer 49

ehh

Answer 50

10 square root of 75=85?

Answer 51

x+y=85

x=85-y

-----------------

75x+100y=85^2

75x+100y=7225

75(85-y)+100y=7225

solve for y

Answer 52

ahh

Answer 53

ehh

Answer 54

I did it too fast the first time, sorry. I re-did it and got it right. If you don't get the answer from the other helpers, let me know and I can show you.

Answer 55

y=34

Answer 56

good

Answer 57

that's the answer

Answer 58

ty

Answer 59

yes. that's what I also got.

Answer 60

these problems are from the PSAT

Answer 61

I want to solve them efficiently in order to do well in the test

Answer 62

I want to get at least a 200 on my PSAT

Answer 63

You're on your way. Good luck on the PSAT.

Answer 64

ty

Answer 65

see you guys later