Question

The number of girls who do wear a watch is double the number who doesn't but the number of boys who do not wear a watch is double the number who does if i tell you the number of girls in my class is double the number of boys can you tell me the number i teach

Answer 1

Answer:

Let number of girls who do not wear a watch = x, where x is any natural number.

Number of girls who wear a watch =2 x

⇒Total number of Girls in the class= x + 2 x= 3 x

Number of Boys who wear the watch = y,where y is any natural number.

Number of Boys who do not wear the watch = 2 y

⇒Total number of Boys in the class=y +2 y=3 y

It is also given that ,⇒ Total number of Girls = 2 × Total number of Boys

  → 3 x = 2 × 3 y

  → x= 2 y---------(1)

Total number of students in the class

                                  = 3 x +  3 y

                                  =3 × 2 y+3 y-------(Using 1)

                                 = 6 y +3 y

                                = 9 y,

So, the number of students i teach will be multiple of 9.

Which can be =9,18,27,36,45,....