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

Answer:

20

Step-by-step explanation:

Let total students be x.

x(50/100) = x/2 have age less than 10.

x/20 are 10 years old

x/10 are older than 10 and younger than 12

remaining = x - (x/2 +x/20 +x/10) = 7x/20 are older than 12

=> 7x/20 = 70 => x = 200

No. of 10 years old = x/10 = 20