Question

There are 27 red or blue marbles in the bag. The number of red marbles is 5 less than 3 times of the blue marbles. How many red marbles are in the bag? How many blue marbles are in the bag?

Answer 1

Let

x--------> The number of red marbles

y--------> The number of blue marbles

we know that

$x+y=27\\ x=27-y$

equation $1$

$x=3y-5$

equation $2$

equate equation $1$ and equation $2$

$27-y=3y-5\\ 3y+y=27+5\\ 4y=32\\ y=8$

$x=3*8-5\\ x=19$

therefore

the answer is

The number of red marbles is $19$

The number of blue marbles is $8$

Answer 2

27=3x-5+x
27+5=4x-5+5
4x=32
4x/4=32/4
x=8
There are 8 blue marbles and 19 red marbles.