Question

If class mark is 10 and class width is 6 then find the class.

Answer 1

Let x be the upper class limit and y the lower class limit.

class mark = 10   ..[given]

class mark = `(x + y)/2`

10 = `(x + y)/2`

x + y = 20    ...(i)

class width = 6    ...[given]

x - y = 6     ....(ii)

Adding equation (i) and (ii)

   x + y = 20
+ x - y = 6    

2x = 26

x = `26/2`

x = 13

Putting the value x = 13 in equation (i),

x + y = 20

13 + y = 20

y = 20 -13

y = 7

∴ the class is 7-13.