GMAT Quant Practice Questions

Probability of Independentevent Events | GMAT Probability Q9

This GMAT quant practice question is a discrete probability problem solving question. The concept tested in this question is to find the probability of selecting a red ball from one of the two bags.

Question 9: Bag x contains 3 red and 5 black balls and bag y contains 4 red and 4 black balls. One bag is selected at random and from the selected bag one ball is drawn. What is the probability that the ball drawn is red?

1. $$frac{7}{8}$ 2. $\frac{7}{16}$ 3. $\frac{3}{16}$ 4. $\frac{4}{5}$ 5. $\frac{9}{16}$ Get to Q51 in GMAT Quant Online GMAT Course @ INR 3500 Video Explanation GMAT Live Online Classes Starts Tue, June 22, 2021 Explanatory Answer | GMAT Probability of Independent Events Bags x and y are equally likely to be selected. The probability of selecting a red ball = probability of selecting a red ball from bag x + probability of selecting a red ball from bag y. Probability of selecting a red ball from bag x = probability of selecting bag x * probability of selecting red ball from it. = $\frac{1}{2}$ × $\frac{3}{8}$ = $\frac{3}{16}$ Probability of selecting a red ball from bag y = probability of selecting bag y * probability of selecting red ball from it. = $\frac{1}{2}$ × $\frac{4}{8}$ = $\frac{4}{16}$ Probability that the ball drawn is red = $\frac{3}{16}$ + $\frac{4}{16}$ = $\frac{7}{16}$ Choice B is the correct answer. GMAT Online Course - QuantTry it free! Register in 2 easy steps and Start learning in 5 minutes! Already have an Account? GMAT Live Online Classes Next Batch Jun 22, 2021 GMAT Coaching in Chennai Next Batch after Lockdown GMAT Coaching in Chennai Sign up for a Free Demo of our GMAT Classes in Chennai GMAT Sample Questions | Topicwise GMAT Questions Where is Wizako located? Wizako - GMAT, GRE, SAT Prep An Ascent Education Initiative 14B/1 Dr Thirumurthy Nagar 1st Street Nungambakkam Chennai 600 034. India How to reach Wizako? Phone:$91) 44 4500 8484
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