Question

Only red and blue marbles in a box. Probability of choosing a red marble at random is one fourth. If there ar 132 blue marbles, how many marbles are in the box?

Answer 1

`x` - the total number of marbles

`|\Omega|=x\\|A|=x-132\\\\P(A)=(1)/(4)=(x-132)/(x)\\\\(1)/(4)=(x-132)/(x)\\x=4(x-132)\\x=4x-528\\3x=528\\x=176`

There are 176 marbles in the box.