# CAT Quantitative Aptitude Questions | CAT Permutation and Combination Questions

###### CAT Questions | Permutation Probability | Number Theory CAT Questions

The question is from Permutation and Combination. A question which combines number theory and probability. We need to find out the probabilty of a multiple of 7 being a multiple of 5. This section hosts a number of questions which are on par with CAT questions in difficulty on CAT Permutation and Combination, and CAT Probability.

Question 19: N is a 3-digit number that is a multiple of 7; what is the probability that it will be a multiple of 5?

1. $$frac{1}{5}\\$ 2. $\frac{11}{54}\\$ 3. $\frac{13}{64}\\$ 4. $\frac{13}{66}\\$ ## 🎯 Huge Discount: 3,500 off on Online CAT Course. Till June 1. Register now! #### 2IIM : Best Online CAT Coaching. ### Video Explanation ## Best CAT Coaching in Chennai #### CAT Coaching in Chennai - CAT 2020Online Batches Available Now! ### Explanatory Answer ##### Method of solving this CAT Question from Permutation and Combination: A combination of Probability and Number Theory gives a perfect question. N is a three digit multiple of 7. N could be 105, 112, 119, 126…..994. Or, 15 * 7, 16 * 7…..142 * 7. Or there are 142–14 = 128 numbers. Within these we need to locate the multiples of 5. Or, we need to isolate multiples of 35. Or, we need to see how many numbers there are in the list 105, 140, 175…..980. 35 * 3, 35 * 4…35 * 28… Or, there are 26 such numbers. Probability $\frac{26}{128}\\$ = $\frac{13}{64}\\$ The question is "what is the probability that it will be a multiple of 5?" ##### Hence the answer is "$\frac{13}{64}\\$" Choice C is the correct answer. ###### 🎯 Huge Discount: 3,500 off on Online CAT Course. Till June 1. Register now! ###### Best Indore IPM & Rohtak IPM CoachingSignup and sample 9 full classes for free. Register now! ###### Already have an Account? ###### CAT Coaching in ChennaiCAT 2020Enroll at 40,000/- Online Classroom Batches Starting Now! ###### Best CAT Coaching in ChennaiRegister Online, get Rs 7000/- off Attend a Demo Class ## CAT Preparation Online | CAT Permutation and Combination; Probability Videos On YouTube #### Other useful sources for Permutation and Combination Questions | Probability Questions ##### Where is 2IIM located? 2IIM Online CAT Coaching A Fermat Education Initiative, 58/16, Indira Gandhi Street, Kaveri Rangan Nagar, Saligramam, Chennai 600 093 ##### How to reach 2IIM? Phone:$91) 44 4505 8484
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