Question

In a school 50% of the students are younger than 10, 1/20 are 10 years old and 1/10 are older than 10 but younger than 12, the remaining 70 students are 12 years or older. How many students are 10 years old?

Answer 1

10 students

Explanation:

Given :-

50% younger than 10

1/20 (or 5%) are 10

1/10 (or 10%) are older than 10 but younger than 12

Remaining students = 100% - 50% - 10% - 5%

= 35%

= 70 students

Total students

=> 7T/20 = 70

=> 7T = 1400

=> T = 200

10 year old students

= T x 5%

= 200 x 1/20

= 10 students

Answer 2

Given :

`50\%`younger than
`10`

`(1)/(20)`(or 5%) are 10

`(1)/(10)` (or 10%) are older than 10 but younger than 12

☆Remaining students =
`100\% -50\% - 10\% - 5\%`

»
`35\%`

»
`{{\bold{{{{{ \pink{70 \: students}}}}}}}}`

☆Total students

↣
`(7 \: total)/(20) = 70`

↣
`7 \: total = 1400`

↣
`{{\bold{{{{{ \pink{total = 200}}}}}}}}`

☆10 year old students

↣
`total * 5\%`

↣
`200 * (1)/(20)`

↣
`{{\bold{{{{{ \pink{10 \: students}}}}}}}}`