Students

After the fifth-grade class left 20% of students. In the seventh grade were added 2 pupils, in the eighth 1 pupil, in the ninth, the number has not changed, but it is now tenth students less than it was in the fifth grade.

How many pupils are in the 9th grade now?

Correct result:

d =  27

Solution:


b=a - 0.20 a
c = 2+b
d = c+1
d = a - 0.10a

b=a - 0.20•a
c = 2+b
d = c+1
d = a - 0.10•a

0.8a-b = 0
b-c = -2
c-d = -1
0.9a-d = 0

a = 30
b = 24
c = 26
d = 27

Calculated by our linear equations calculator.



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