Question

I asked my daughter how many students are there in her class. She said it is equal to the sum of 3 consecutive natural numbers. Moreover, it is also equal to the sum of the two natural numbers following those 3 consecutive natural numbers. What is the answer to my questions?

Answer 1

Answer: Let's call the smallest of the 3 consecutive natural numbers "n". The other two numbers are "n+1" and "n+2". The sum of these 3 numbers is "3n + 3"

Also, the sum of the two numbers following these 3 consecutive natural numbers is (n+3) + (n+4) = 2n + 7

We know that these two expressions are equal:

3n + 3 = 2n + 7

By solving this equation we can find the value of n.

Subtracting 3 from both sides: 3n = 4

Dividing by 3: n = 4/3

Since n is a natural number, n has to be the integer 1.

So the three consecutive natural numbers are 1, 2, 3 and the sum of the students in the class is 6, which is also the sum of the next two natural numbers 4 and 5.

Therefore, there are 6 students in her class.

Explanation: