Abag contains green marbles and blue marbles, 16 in total. The number of green marbles is 8 less than 2 times the number of blue marbles, How many green marbles are there?

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Answer 1 · 2016-12-10T07:49:40

Assign a variable for the number of blue marbles.

In this case, let's use y.

To find the number of green marbles, assign an expression following information from the question, which gives you;

$(2 y - 8) + y = 16$ $(2y-8)+y = 16$

Here, the expression $2 y - 8$ $2y-8$ will give you the total number of green marbles, hence you can just solve the equation;

$3 y - 8 = 16$ $3y-8 = 16$
$16 + 8 = 3 y$ $16+8 = 3y$
$24 = 3 y$ $24 = 3y$
$y = 8$ $y=8$

There are 8 blue and 8 green marbles.

Substitute 8 for y to find the green marbles;

$2 (8) - 8 = 8$ $2(8)-8 = 8$