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What level is this question in the maths curriculum?
Posted: Fri May 15, 2009 9:15 am
by essex-mum18
Find the value of a and b in the following question.
2 to the power of a x 5 to the power of b =200
I use prime factorization to work out 2x2x2x5x5, therefore the value of a =3 and the value of b=2
I wonder what level would you expect this sort of question in the exam? Thanks in advance.
Posted: Fri May 15, 2009 11:35 am
by SunlampVexesEel
I can't answer the question on level... we'll have to wait for a teacher to do that...
... but... it does seem pretty simple... i.e even if you don't factor it... there is an obvious 25x8 there. Factoring, given that 2 and 5 are prime, of course is the correct approach.
I'll try it out of the DCs later
Regards
SVE
Posted: Fri May 15, 2009 4:35 pm
by Guest55
About a level 7 -ish
Posted: Tue May 19, 2009 10:34 pm
by dadofkent
Surely it is simpler than that. It cannot be 5 cubed because that will give 125, therefore it has to be 5 squared. The rest follows.
QED
Posted: Tue May 19, 2009 10:47 pm
by Guest55
It's hard to judge because the full question hasn't been quoted - if it's all written in algebraic form it makes it harder.
Posted: Tue May 19, 2009 11:07 pm
by Bewildered
and this one, pls...
1/x=3/4
What is the value of x?
Posted: Tue May 19, 2009 11:10 pm
by hermanmunster
er bit late - back from work and out with the beer ....
1/x=3/4
multiply through by x -> 1=3x/4
multiply through by 4 -> 4=3x
divide through by 3 -> 4/3=x
x= 4/3 or 1.33333333333333333333333
- oops there's a simpler way I've just realised
Posted: Tue May 19, 2009 11:19 pm
by Bewildered
Thanks Herman, that's what I made it. But confusion is, are you allowed to make the denominator a mixed number???
Posted: Tue May 19, 2009 11:20 pm
by hermanmunster
now I'm feeling bewildered!!! what's a mixed number?
Posted: Tue May 19, 2009 11:23 pm
by Bewildered
sorry, I meant a whole number part and a decimal/fraction part like 1.33, by mixed number.
Normally you'd only have a whole number as a denominator. (well in the lower types of maths I've done, you do
)