CAT Practice Question and Answer
8Q: Maheshwari wants to buy 7 floors in an 68 storied building whose numbering stars from 1 upto 68. But she has to follow certain rules which are as follows : 1) None of the floor should be a prime number 2) None of the digit of the floor should be a prime number 3) Maheshwari cannot buy the 1st floor as it is being assigned to the architect. So how many options are left with Maheshwari to buy the floors ? 1289 05b5cc709e4d2b4197774f2a8
5b5cc709e4d2b4197774f2a8- 111false
- 217true
- 313false
- 419false
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Answer : 2. "17"
Explanation :
Answer: B) 17 Explanation: Since floor starts form the 1 therefore 2 will be the 1st floor.Form 1 to 10 only 4,6,8,9,10 are not prime.Form 11 to 20 only 14 ,16,18 are not prime also non of their digits are prime.From 21 to 30 each number has a prime number so it must no be consider.In between 40 to 49 we have to consider only 40,44,46,48,49.50 to 59 follow either of the condition so we have too neglect it.In between 60 to 68 60,64,66,68.total option = 17.
Q: What is the sum of all 3 digits number that can be formed using digits 0,1,2,3,4,5 with no repitition ? 1404 05b5cc709e4d2b4197774f2a3
5b5cc709e4d2b4197774f2a3- 128450false
- 226340false
- 332640true
- 436450false
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Answer : 3. "32640"
Explanation :
Answer: C) 32640 Explanation: We know that zero can't be in hundreds place. But let's assume that our number could start with zero. The formula to find sum of all numbers in a permutation is 111 x no of ways numbers can be formed for a number at given position x sum of all given digits No of 1 s depends on number of digits So,the answer us 111 x 20 x (0+1+2+3+4+5) = 33300 We got 20 as follows. If we have 0 in units place we can form a number in 4*5 ways. This is for all numbers. So we have substituted 20 in formula. Now, this is not the final answer because we have included 0 in hundreds place. so we have to remove the sum of all numbers that starts with 0. This is nothing but the sum of all 2 digits numbers formed by 1 2 3 4 5. Because 0 at first place makes it a 2 digit number. So the sum for this is 11 x 4 x (1+2+3+4+5). =660 Hope u understood why we use 4. Each number can be formed in 4x1 ways So, the final answer is 33300-660 = 32640
Q: A sequence of natural number 2,3,5,6,10. Such that no square and no cube occurs in the term. Find the 300th term of sequence ? 1278 05b5cc709e4d2b4197774f29e
5b5cc709e4d2b4197774f29e- 1322false
- 2319false
- 3321false
- 4320true
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Answer : 4. "320"
Explanation :
Answer: D) 320 Explanation: 1 to 300 = 300 numbers squares btwn 1 to 300 = 1,4,9,16,25,36,49.....289 i.e, total 17cubes = 1,8,27,64,125,216 i.e, 5 now 1 and 64 are common so total numbers that should be removed ( 17+5-2= 20 )total 20 term removed so 300th term would be 320
Q: Sambhu buys rice at Rs. 10/kg and puts a price tag on it so as to earn a profit of 20%. However, his faulty balance shows 1000 gm when it is actually 800 gm. What is his actual gain percentage ? 1623 05b5cc709e4d2b4197774f299
5b5cc709e4d2b4197774f299- 150%true
- 225%false
- 375%false
- 460%false
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Answer : 1. "50%"
Explanation :
Answer: A) 50% Explanation: CP of 1000gm = Rs. 10SP of 800gm = Rs. 12SP of 1000gm =12x1000/800 = Rs. 15 Now take 1000gm as reference to calculate profit.Profit=SP-CP=15-10=Rs. 5Profit % = 5x100/10 = 50%
Q: The wages of labourers in a factory increases in the ratio 22:25 and there was a reduction in the number of labourers in the ratio 15:11. Find the original wage bill if the present bill is Rs. 5000 ? 4404 05b5cc709e4d2b4197774f294
5b5cc709e4d2b4197774f294- 1Rs. 5500false
- 2Rs. 6000true
- 3Rs. 6200false
- 4Rs. 6350false
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Answer : 2. "Rs. 6000"
Explanation :
Answer: B) Rs. 6000 Explanation: The wages of labourers in a factory increases in the ratio 22:25 and there was a reduction in the number of labourers in the ratio 15:11. Find the original wage bill if the present bill is Rs 5000 ?Ratio of increase of wages = 22:25Ratio of decrease of labourers = 15:11Compound ratio of wages of labourers = 22 x 15 : 25 x 11 = 330:275Final bill = Rs. 5000For 275 ratio wages = Rs. 5000For 1 ratio wages = 5000/275For 330 ratio wages = 5000/275 x 330 = Rs. 6000
Q: What was the day on 2nd Jan 1901 ? 4249 05b5cc709e4d2b4197774f28f
5b5cc709e4d2b4197774f28f- 1Tuesdayfalse
- 2Wednesdaytrue
- 3Mondayfalse
- 4Thursdayfalse
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Answer : 2. "Wednesday"
Explanation :
Answer: B) Wednesday Explanation: 2nd Jan 1901 means(1900 years and 2 day)Now, 1600 years have 0 odd day300 years have 1 odd day2 days has 2 odd dayTotal no. of odd days = 0 + 1 + 2 = 3 daysHence, the day on 2nd Jan 1901 was Wednesday.
Q: The difference of two numbers is 14. Their LCM and HCF are 441 and 7. Find the two numbers ? 3099 05b5cc709e4d2b4197774f267
5b5cc709e4d2b4197774f267- 163 and 49true
- 264 and 48false
- 362 and 46false
- 464 and 49false
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Answer : 1. "63 and 49"
Explanation :
Answer: A) 63 and 49 Explanation: Since their HCFs are 7, numbers are divisible by 7 and are of the form 7x and 7y Difference = 14 => 7x - 7y = 14=> x - y = 2 product of numbers = product of their hcf and lcm=> 7x * 7y = 441 * 7=> x * y = 63 Now, we havex * y = 63 , x - y = 2=> x = 9 , y = 7 The numbers are 7x and 7y=> 63 and 49
Q: There are 41 students in a class, number of girls is one more than number of guys. we need to form a team of four students. all four in the team cannot be from same gender. number of girls and guys in the team should NOT be equal. How many ways can such a team be made ? 1800 05b5cc709e4d2b4197774f262
5b5cc709e4d2b4197774f262- 149450false
- 250540true
- 346587false
- 452487false
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Answer : 2. "50540"
Explanation :
Answer: B) 50540 Explanation: Given G + B= 41 and B = G-1 Hence, G = 21 and B = 20Now we have 2 options, 1G and 3M (or) 3G and 1M(2G and 2M or 0G and 4M or 4G and oM are not allowed), Total : C121×C320+C321×C120= 50540 ways.

