2 A bag contains only red and blue marbles. Yasmine takes one marble a...
Let the no. of red marbles = n.....and that of blue marbles = y....then in 1st situation..prob of taking red ball = n/(n+y) = 1/5...let n+y be x so that 5n=x.......and when 5more red marbles are added to the bag..then the prob of taking out the red marbl becomes = (n+5)/(5n+5 )=1/3...by solving this eq... n= 5....then from the eq 5n= x ...we get x= 25.... and x= n+y....therefore y= 20...so no. of red marbles =5 ... and blue =20
2 A bag contains only red and blue marbles. Yasmine takes one marble a...
Given Information:
- The probability of picking a red marble from the bag initially is 1 in 5.
- Yasmine returns the marble to the bag and adds five more red marbles.
- The probability of picking a red marble from the bag after adding the extra red marbles is 1 in 3.
Let's solve the problem step by step:
Step 1: Determine the initial probability of picking a red marble:
- Let's assume there are 'r' red marbles and 'b' blue marbles in the bag initially.
- The total number of marbles in the bag is 'r + b'.
- The probability of picking a red marble initially can be expressed as: P(red) = r / (r + b).
- According to the problem, P(red) = 1/5.
Step 2: Determine the probability of picking a red marble after adding the extra marbles:
- Yasmine returns the marble to the bag, so the total number of marbles in the bag remains the same.
- Yasmine adds five more red marbles to the bag, resulting in 'r + 5' red marbles in the bag.
- The probability of picking a red marble after adding the extra marbles can be expressed as: P(red) = (r + 5) / (r + 5 + b).
- According to the problem, P(red) = 1/3.
Step 3: Solve the equations:
- We have two equations with two unknowns: r / (r + b) = 1/5 and (r + 5) / (r + 5 + b) = 1/3.
- Let's solve these equations to find the values of 'r' and 'b'.
Step 4: Solve equation 1:
- Multiply both sides of the equation by (r + b) to eliminate the denominator: r = (r + b) / 5.
Step 5: Solve equation 2:
- Multiply both sides of the equation by (r + 5 + b) to eliminate the denominator: r + 5 = (r + 5 + b) / 3.
Step 6: Simplify equation 4:
- Multiply both sides of the equation by 5 to eliminate the fraction: 5r = r + b.
Step 7: Simplify equation 5:
- Multiply both sides of the equation by 3 to eliminate the fraction: 3(r + 5) = r + 5 + b.
Step 8: Simplify equation 6:
- Distribute 3 on the left side of the equation: 3r + 15 = r + 5 + b.
Step 9: Simplify equation 7:
- Combine like terms on the right side of the equation: 3r + 15 = r + b + 5.
Step 10: Simplify equation 8:
- Subtract r from both sides of the equation: 2r + 15 = b + 5.
Step 11: Simplify equation 9:
- Subtract 5 from both sides of the equation: 2r
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