Answer:
9
Step-by-step explanation:
Given that the sample size is 45 blocks
Let number of red blocks in the bag to be x
Then the probability of chosing a red block will be x/45
Given that the probability of choosing a red block is 1/5 then you can form the expression;
x/45 = 1/5 ---------------find the value of x by performing cross multiplication
5x=45*1
5x/5=45/5
x=9
Answer
Julia put 9 red blocks in the bag.