## Vineet Loomba is teaching live on Unacademy Plus

SOLVED PRACTICE PROBLEMS PROBABILITY JEE MAIN RANK BOOSTER COURSE PREPARED BY: ER. VINEET LOOMBA ITIAN IIT-JEE MENTOR

FOR 100% SUCCESS IN JEE MAIN AND ADVANCED (IIT-JEE) ABOUT ME B.Tech. From IIT Roorkee -$ IIT-JEE Mentor Since 2010. Youtube Channel with 10k Active Followers & Founder @ vineetloomba.com * Follow me @ https://unacademy.com/user/vineetloomba to get unacademy updates or search me on Google * Share among your peers as SHARING is CARING!!

FOR 100% SUCCESS IN JEE MAIN AND ADVANCED (IIT-JEE) Other Detailed Courses Made so far on Unacademv: V Strategy for JEE Main and Advanced V Sets, Relations and Functions V Trigonometry V Applications of Derivatives Limits, Continuity. Differentiability V Indefinite Integration V Definite Integration Complex Number V Logarithmic Functions V Sequences Series V Most Important Questions in IIT-JEE Permutations Combinations Binomial Theorem V Straight Lines V Applications of Integrals MathematicS V Parabola (Detailed Course) v Inverse Trigonometry V Mathematical Reasoning V Ellipse (Detailed Course) V Hyperbola V Differential Equations Circles (Detailed Course) V Probability Upcoming Courses next month: > Differential Equations ER. VINEET LOOMBA (IIT RooRKee) MATHEMATICS FOR IIT-I

100% SUCCESS IN JEE MAIN AND ADVANCED (IIT-JEE) Ex. A speaks truth in 75% cases and B in 80% cases. What is the probability that they contradict each other in stating the same fact? (A) 7/20 (C) 3/20 (B) 13/20 Sol There are two mutually exclusive cases in which they contradict each other i.e. AB and AB. Hence Required probability -PAB+ ,-PAB) + P (AB) P(A) P(B) + P( ) P (B) 4 5 4 5 20 SUCCESS IN JEE MAIN 2019 ER. VINEET LOOMBA (IIT RooRKEE)

100% SUCCESS IN JEE MAIN AND ADVANCED (IIT-JEE) Ex. The letters of the word HIRDESH are written in a row randomly. The probability of the words starting with H and ending with H is- (A) 1/21 (B) 2/21 (D) None of these 7! sol. Total no. of case s = Since H is written at first and last places, therefore at the remaining 5 places, 5 letters can be written in 5! ways Required probability7/21 21 SUCCESS IN JEE MAIN 2019 ER. VINEET LOOMBA (IIT RooRKEE)

100% SUCCESS IN JEE MAIN AND ADVANCED (IIT-JEE) Ex. Three numbers are selected one by one from whole numbers 1 to 20. The probability that they are consecutive integers is- (A) 1/380 (C) 3/20 Total number of sequences of 3 numbers selected one by one from whole numbers 1 to 20 20 x19 x 18 Now sequences which will contain three consecutive integers are (1, 2, 3) (2, 3, 4), (3, 4, 5). (18,19,20). These are 18 sequences. Hence (B) 3/190 (D) None of these Sol. 18 :. required probability 20 x19 x 18 380 SUCCESS IN JEE MAIN 2019 ER. VINEET LOOMBA (IIT RooRKEE)

100% SUCCESS IN JEE MAIN AND ADVANCED (IIT-JEE) Ex. A box contains 20 cards. The letter I is written on 10 cards and T is written on other 10 cards, 3 cards are chosen randomly and are kept in the same order. The probability of making the word IIT is- (A) 9/80 (C) 4/27 (B) 1/80 (D) 5/38 Sol. Required probability P (I on first card) x P (I on second card) x P (T on third card) 10 9 105 20 19 18 38 SUCCESS IN JEE MAIN 2019 ER. VINEET LOOMBA (IIT RooRKEE)

100% SUCCESS IN JEE MAIN AND ADVANCED (IIT-JEE) Ex. If two events A and B are such that P (A) 0.3, P (B)0.4 and P (AB) 0.5, then P AuB equals- Sol. We have P (AB) P (A)-P (AB) P(A)+P (B)-P (AB) P (A)+P (B)-P (AB) 0.7-0.5 0.2 1 =0.7+06-05-08-4 SUCCESS IN JEE MAIN 2019 ER. VINEET LOOMBA (IIT RooRKEE)

FOR 100% SUCCESS IN JEE MAIN AND ADVANCED (IIT-JEE) ENROL for this Course (Free) Enroll 439 Recommend Lessons (Like) E Rate and Review the Course .Comments . Sharing with friends 15 1. 68 111 ratings 21 reviews Share ER. VINEET LOOMBA (IIT RooRKEE) MATHEMATICS FOR IIT-IEE