A bag contains yellow marbles and red marbles, 65 in total. The number of yellow marbles is 5 more than 4 times the number of red marbles. How many yellow marbles are there?

53

Step-by-step explanation:

You make formulas for it.

Y = yellow marble and r = red marbles

So we know y+r=65

and y=5+4r because there are 5 more (plus) and 4 times (multiply) yellow marbles

so now we make y+r=65 to have r = so you subract to the y so you get r = 65-y

now you plug that into your other formula

y = 5 + 4 (65-y)

distribute

y=5 + 260-4y

add common numbers

y=265-4y

add 4y from both sides

5y=265 (it is 5y because there is already a 1y on that side and 1y+4y=5y

then divied both sides by 5 y=53