Question

Erik thinks of a prime number between 20 and 30. His number is x% of 125. Work out one possible value of x

Answer 1

There are two prime numbers between 20 and 30: 23 and 29.

To find the percentage each number is of 125, you’d divide the number by 125 and move the decimal in the answer 2 places to the right to turn it to percentage notation (from decimal notation), so you’d solve 23/125 and 29/125.

23/125= .184
Moving the decimal two places to the right makes this 18.4%

29/125= .232
Moving the decimal two places to the right makes this 23.2%

X has two possible values of which you are to pick/use only one: 18.4 and 23.2

Answer 2

18.4%

Explanation:

- Prime numbers between 20 and 30: 23, 29

Let's use 23. We now have to find the % of 23 of 125.

23/125 = 0.184 ( / = divided by)

To turn this into a %, we multiply by 100.

0.184 x 100 = 18.4

Therefore, x may equal 18.4

To check:

18.4% of 125

18.4 x 125 =

23

Therefore, 18.4% is the correct answer.

Hope this helps.

- profparis