Incomplete Question (See Complete Question Below)
A bag contains 10 red marbles and 15 green marbles.If Yuki selects a marble from the bag without looking, what is the probability that she will pull a red marble?
A-1/5
B-2/5
C-1/2
Answer:
The probability of pulling a red marble is 
Step-by-step explanation:
Given
Red Marble = 10
Green Marble = 15
Required
The probability of picking a red marble
First, the total number of marble has to be calculated
Total = Red Marble + Green Marble
Total = 10 marbles + 15 marbles
Total = 25 marbles
The probability of an event is often calculated by dividing the number of required outcomes by the number of possible outcomes.
In this case, the probability of pulling a red marble is calculated as follows:

Where P(R) represents probability of pulling a red marble
n(R) represents number of red marbles
n(R) = 10
T represents total number of marbles
T = 25
By substitution,
becomes

Reduce fraction to lowest term by dividing the numerator and denominator by 5

Hence, the probability of pulling a red marble is 