before explaining dis i wud like to explain a funda dat is of d same type.....d question is like...there are two numbers A and B and their product is constant. if A is decreased by 10 %, how much percent wud there be a change in B to make up for the constant product.
logically thinking......if the product has to be constant....B has to increase.....so this is the first step...nw goin a little mathematically,
we know A x B = k ( say a constant), therefore B = k/A
A is decreased by 10 %.....so A' becomes 0.9A
new value of A = A' = 0.9A
new value of B = B'
Product has to be constant, therefore A' x B' = k
or ( 0.9A ) x B' = k
or ( 0.9B' ) X A = k
or 0.9 B' = k/A
now we know k/A = B
or 0.9 B' = B
or B' = (10/9) X B
or B' = 11.11B
so B has to be increased to 11.11 %.
same funda is to be applied to ur question.
infact ur question is too simple to apply any mathematics..i wonder why have u asked d question...if Y is decreased by 10%, den to keep d ratio same X has to be decreased and to 10% only.
But I think we should all remember these simple stuffs to avoid doing so many calculations in exam. With CAT becoming so tough and reasoning based we should avoid calculations as much as possible.
Please refer to the below link and try to understand the logic and remember the table. It ‘ll be of immense help.
hey i gona tell u...it was jus d explanation......obviously when u understand d concept u need to go to d depth.....once u start prctcin it dsnt take dat time......an obviously i am aware f dose percentge conversions......i knw if u start solvin it like d way i hav explained it will take much time.......
before explaining dis i wud like to explain a funda dat is of d same type.....d question is like...there are two numbers A and B and their product is constant. if A is decreased by 10 %, how much percent wud there be a change in B to make up for the constant product.
logically thinking......if the product has to be constant....B has to increase.....so this is the first step...nw goin a little mathematically,
we know A x B = k ( say a constant), therefore B = k/A
A is decreased by 10 %.....so A' becomes 0.9A
new value of A = A' = 0.9A
new value of B = B'
Product has to be constant, therefore A' x B' = k
or ( 0.9A ) x B' = k
or ( 0.9B' ) X A = k
or 0.9 B' = k/A
now we know k/A = B
or 0.9 B' = B
or B' = (10/9) X B
or B' = 11.11B
so B has to be increased to 11.11 %.
same funda is to be applied to ur question.
infact ur question is too simple to apply any mathematics..i wonder why have u asked d question...if Y is decreased by 10%, den to keep d ratio same X has to be decreased and to 10% only.
simple!!
But I think we should all remember these simple stuffs to avoid doing so many calculations in exam. With CAT becoming so tough and reasoning based we should avoid calculations as much as possible.
Please refer to the below link and try to understand the logic and remember the table. It ‘ll be of immense help.
http://www.cat4mba.com/math-e-boom/vedic-mathematcis-1
hey i gona tell u...it was jus d explanation......obviously when u understand d concept u need to go to d depth.....once u start prctcin it dsnt take dat time......an obviously i am aware f dose percentge conversions......i knw if u start solvin it like d way i hav explained it will take much time.......
thnx fer d link....
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