Question

suppose y varies directly as X, and Y equals 16 when x equals 8 find y when x equal 16

Answer 1

when
$y = x \\ y = 16 \\ x = 8$
you would have to use comon multiples to find what both numbers have in common, a short way of finding this would be
$16 \div 8 = a$
where (a) is the answer of the equation, (a) would be 2 because 8*2=16 meaning
$y = 2x$

Answer 2

$y = 16 \\ x = 8 \\ x = 8 \times 2 = 16 \\ y = 16 \times 2 = 32$
so when x(8) equals 16 it would mean 8 is multiplied by 2 and so once x(8) is multiplied by 2 y(16) would also have to be multiplied by 2 which is 32
so y =32 I'm sorry if I'm wrong