Question

11. Students of a class are made to sit in
rows of equal number of chairs. If
number of students is increased by 2
in each row, then the number of rows
decreases by 3. If number of students
is increased by 4 in each row, then the
number of rows decreases by 5. What
is the number of students in the class ?
(a) 100
(b) 105
(c) 110
(d) 120​

Answer 1

Answer:

I think number of students must be 105 I am not sure you just check it once at Google or at book

Answer 2

Answer:

(d)120

Step-by-step explanation:

let the number of students be 'x' and rows be 'y' respectively.

a.c.p.

(x+2)(y-3)=xy (total no.of students=students(x)×rows(y))

3x-2y+6=0------(1)

(x+4)(y-5)=xy

5x-4y+20=0------(2)

Now,

eq(1)×2-eq(2)

2(3x-2y+6)-(5x-4y+20)=0

6x-4y+12-5x+4y-20=0

x-8=0

x=8

and

3(8)-2y+6=0 (sub 'x' in eq(1))

30+2y=0

y=15

so,the no.of total students in the class=xy=8×15=120