Alex spend 3/4 of his money. he gave 1/4 of the remainder to his sister. he had $120 left. how much did have in the beginning?

X = amount of money he had in the beginning

Because he spent 3/7, he has 4/7 left.

(4/7x)

We have to take 1/4 off THIS value. He has 3/4 of this value left.

(4/7x)1/4

Now, lets set it up as an equation

(4/7x)1/4 = 120

Multiply both sides by 4

4/7x = 480

Multiply both sides by 7/4

x = 480 * 7/4
x = 840

Hope his helped!