Saturday, January 23, 2010

22 Jan (01): Prime Factorisation (continues...)

Textbook p9 #25:
The Prime factorisation of a number is 2^4 X 3^5 X 7^2 X 11.
Write down 3 factors of the number that are greater than 100.
(Hint: 16 X 11 = 176, which is a factor.)
2^4 X 3^5 X 7^2 X 11 = 2095632
The factors of 2095632 is 176,538 and 891
The Prime factorisation of two numbers are 2 X 3^2 X 7^3 X 13 and3 X 7^2 X 13^3 X 17 .
Write down 3 common factors of the numbers.
2 X 3^2 X 7^3 X 13 =80262
3 X 7^2 X 13^3 X 17 =5490303
The three common factors are 1,3,7

1 comment:

  1. Bryan

    Notice that you actually multiplied all the factors given in the index notation to get the original number.
    So, how did you make use of this number to find your answers?

    Amongst the answers you submitted,
    2095632 is divisible by 891 (with no reminder). Hence, 891 is a factor.
    However, 2095632 is not divisible by 176,538. Therefore 176,538 is not a factor.
    So, you've got any idea how to get the 2 other factors (that are greater than 100) for the number 2095632?

    Textbook p9 #26:
    Could you share how you identify these 3 numbers as your answers?

    ReplyDelete