# 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. $\frac{13}{66}\\$ ## Try 2IIM Online CAT Coaching #### Best CAT Online Coaching ### Video Explanation ## Best CAT Coaching in Chennai #### Batches filling fast. Starts Sat, April 27th, 2019 ### 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. ###### Best Online CAT CoachingLearn from 4 time CAT 100 percentiler Register in 2 easy steps and start learning in 30 seconds! ###### Already have an Account? ###### CAT Coaching in Chennai Next Weekend Batch Starts Sat, April 27th, 2019 ###### Best CAT Coaching in ChennaiBatches filling fast Personalised attention, Small batch sizes. ## 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, 10-C, Kalinga Colony, Bobbili Raja Salai K.K.Nagar, Chennai. India. Pin - 600 078 ##### How to reach 2IIM? Phone:$91) 44 4505 8484
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