Three-variables-u-v-and-w-are-related-such-that-u-varies-directly-as-v-and-inversely-as-the-square-of-w-If-v-increases-by-15-and-w-decreased-by-10-find-the-percentage-change-in-u-

Question Number 38636 by pieroo last updated on 27/Jun/18

Three variables u, v and w are related such that

u varies directly as v and inversely as the square of

w . If v increases by 15 % and w decreased by 10 %,

find the percentage change in u .

Answered by MrW3 last updated on 28/Jun/18

u = k \frac{v}{w^{2}}

v_{2} = 1.15 v_{1} (i n c r e a s e b y 15 %)

w_{2} = 0.90 w_{1} (d e c r e a s e b y 10 %)

u_{2} = k \frac{1.15 v_{1}}{0 . 90^{2} w_{1}^{2}} = \frac{1.15}{0 . 90^{2}} \times k \frac{v_{1}}{w_{1}^{2}} = \frac{1.15}{0 . 90^{2}} u_{1} = 1.42 u_{1}

\Rightarrow u i n c r e a s e s b y 42 % .

Commented by pieroo last updated on 28/Jun/18

Thanks Sir .

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