IIT JEE Practice Question and Answer
8Q: If A1, A2, A3, A4, ..... A10 are speakers for a meeting and A1 always speaks after, A2 then the number of ways they can speak in the meeting is 1451 05b5cc7b4e4d2b419777508a6
5b5cc7b4e4d2b419777508a6- 19!false
- 29!/2false
- 310!false
- 410!/2true
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Answer : 4. "10!/2"
Explanation :
Answer: D) 10!/2 Explanation: As A1 speaks always after A2, they can speak only in 1st to 9th places and A2 can speak in 2nd to 10 the places only when A1 speaks in 1st place A2 can speak in 9 places the remaining A3, A4, A5,...A10 has no restriction. So, they can speak in 9.8! ways. i.e when A2 speaks in the first place, the number of ways they can speak is 9.8!. When A2 speaks in second place, the number of ways they can speak is 8.8!. When A2 speaks in third place, the number of ways they can speak is 7.8!. When A2 speaks in the ninth place, the number of ways they can speak is 1.8! Therefore,Total Number of ways they can speak = (9+8+7+6+5+4+3+2+1) 8! = 92(9+1)8! = 10!/2
Q: The number of ways that 7 teachers and 6 students can sit around a table so that no two students are together is 1213 05b5cc7b4e4d2b419777508a1
5b5cc7b4e4d2b419777508a1- 17! x 7!false
- 27! x 6!true
- 36! x 6!false
- 47! x 5!false
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Answer : 2. "7! x 6!"
Explanation :
Answer: B) 7! x 6! Explanation: The students should sit in between two teachers. There are 7 gaps in between teachers when they sit in a roundtable. This can be done in 7P6ways. 7 teachers can sit in (7-1)! ways. Required no.of ways is = 7P6.6! = 7!.6!
Q: The number of ways that 8 beads of different colours be strung as a necklace is 2094 05b5cc7b4e4d2b4197775089c
5b5cc7b4e4d2b4197775089c- 12520true
- 22880false
- 34320false
- 45040false
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Answer : 1. "2520"
Explanation :
Answer: A) 2520 Explanation: The number of ways of arranging n beads in a necklace is (n-1)!2=(8-1)!2=7!2 = 2520 (since n = 8)
Q: In How many ways can the letters of the word 'CAPITAL' be arranged in such a way that all the vowels always come together? 940 05b5cc7b4e4d2b41977750897
5b5cc7b4e4d2b41977750897- 1360true
- 2720false
- 3120false
- 4840false
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Answer : 1. "360"
Explanation :
Answer: A) 360 Explanation: CAPITAL = 7 Vowels = 3 (A, I, A) Consonants = (C, P, T, L) 5 letters which can be arranged in 5P5=5! Vowels A,I = 3!2! No.of arrangements = 5! x 3!2!=360
Q: In how many ways the letters of the word 'DESIGN' can be arranged so that no consonant appears at either of the two ends? 1021 05b5cc7b4e4d2b41977750892
5b5cc7b4e4d2b41977750892- 1240false
- 272false
- 348true
- 436false
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Answer : 3. "48"
Explanation :
Answer: C) 48 Explanation: DESIGN = 6 letters No consonants appear at either of the two ends. = 2 x 4P4 = 2 x 4 x 3 x 2 x 1= 48
Q: Using numbers from 0 to 9 the number of 5 digit telephone numbers that can be formed is 1114 05b5cc7b4e4d2b4197775088d
5b5cc7b4e4d2b4197775088d- 11,00,000false
- 259,049false
- 33439true
- 46561false
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Answer : 3. "3439"
Explanation :
Answer: C) 3439 Explanation: The numbers 0,1,2,3,4,5,6,7,8,9 are 10 in number while preparing telephone numbers any number can be used any number of times. This can be done in 105ways, but '0' is there So, the numbers starting with '0' are to be excluded is 94 numbers. Total 5 digit telephone numbers = 105- 94 = 3439
Q: Count the number of triangles and squares in the given figure. 2724 05b5cc7b0e4d2b41977750826
5b5cc7b0e4d2b41977750826- 136 triangles, 7 Squaresfalse
- 238 triangles, 9 Squaresfalse
- 340 triangles, 7 Squarestrue
- 442 triangles, 9 Squaresfalse
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Answer : 3. "40 triangles, 7 Squares"
Explanation :
Answer: C) 40 triangles, 7 Squares Explanation: The figure may be labelled as shown Triangles : The Simplest triangles are BGM, GHM, HAM, ABM, GIN, IJN, JHN, HGN, IKO, KLO, LJO, JIO, KDP, DEP, ELP, LKP, BCD and AFE i.e 18 in number The triangles composed of two components each are ABG, BGH, GHA, HAB, HGI, GIJ, IJH, JHG, JIK, IKL, KLJ,LJI, LKD, KDE, DEL and ELK i.e 16 in number. The triangles composed of four components each are BHI, GJK, ILD, AGJ, HIL and JKE i.e 6 in number. Total number of triangles in the figure = 18 + 16 + 6 =40. Squares : The Squares composed of two components each are MGNH, NIOJ, and OKPL i.e 3 in number The Squares composed of four components each are BGHA, GIJH, IKJL and KDEL i.e 4 in number Total number of squares in the figure = 3 + 4 =7
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Answer :
Explanation :
1. Answer : 2 Explanation : Productivity = Total production/area of Agr.land Productivity of UP = [ (35000+30000+25000) / (30/100) ] = 300000 Productivity of MP = [ (30000+37500+27500) / (25/100) ] = 380000 Productivity of Bihar = [ (22500+27500+25000) / (20/100) ] = 375000 Productivity of Odisha = [ (22500+15000+10000) / (5/100) ]= 950000 Productivity of Haryana = [ (30000+25000+35000) / (8/100) ] = 1125000 Productivity of Punjab = [ (40000+35000+30000) / (12/100) ] = 875000 The Productivity of Haryana is the maximum. 2. Answer : 5 Explanation : Production of Punjab is maximum = 105000 tonnes 3. Answer : 3 Explanation : Production of Wheat in Punjab = 40000 tones Production of Maize in Odisha = 10000 tones Required % = (40000 - 10000)/100 = 300% 4. Answer : 4 Explanation : The ratio of prodution of Rice in Bihar to the production of Wheat in Haryana = 25000 tonnes : 25000 tonnes = 1 : 1 5. Answer : 1 Explanation : Income of MP from export of 40% of Rice at the rate of Rs.30 per kg = Rs.39crore Income of UP from export of 30% of Rice at the rate of Rs.32 per kg = Rs.28.8 crore Required ratio = 39 : 28.8 = 390 : 288 = 65 : 48