If y varies directly as x and y = 198 when x = 22, how do you find y when x = 182?

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Answer 1 · 2015-07-04T19:59:19

$y = 1638$

" $y$ varies directly as $x$ " tells us that for some constant (some number) $k$ , we have"

$y = kx$

We are also told that $y = 198$ when $x = 22$ .

We can use this to find the number $k$ .

$198 =k*22$ so

$k = 198/22 = (11*18)/(11*2) = 18/2 =9$

So we have learned that $y = 9x$

Now, when $x=182$ , we must have $y = 9(182)$
So
$y = 1638$

Answer 2 · 2015-07-04T20:34:09

You can use cross multiplication.

$y_1/x_1=y_2/x_2$ , where $y_1=198;$ $x_1=22;$ $y_2=?;$ $x_2=182$ .

$198/22=y_2/182$

Cross multiply.

$(198*182)/(22)=y_2$

$1368=y_2$

Switch sides.

$y_2=1368$