Jerry has a total of 23 marbles. The marbles are either blue or green. He has three more blue marbles than green marbles. How many green marbles does he have?

Question

lgbasallote · Answer

let x = blue
y = green

x + y = 23

it is also said that there are three more blue than green so

x = 3 + y

let's sub this value of x into the first equation

3 + y +y = 23

3 + 2y = 23

2y = 23 - 3

2y = 20

lgbasallote · Answer

if you divide both sides by 2 you get

y = 10

tehrefore there are 10 green marbles

anonymous · Answer

okay i think it's like this
suppose there are x green marbles 
and since there are three more blue marbles than green marbles, we can say that he has x+3 blue marbles 
so basically 
green=x 
blue=x+3
and total is 23
so x+x+3=23
so x=10
10 green marbles