@ziatron 9/8
The crew of an 8 member rowing team is to be chosesn from 12 members, of which 3 must row on one side and 2 must row on another side only.Find the number of ways in arranging the crew with 4 members on each side.
a) 40,320.
b) 30,240.
c) 60,480.
d) 10,080.
e) none of this.
Arun Sharma P n C,LOD-II page no 526,Q 10.
Please explain me logic as ans ka logic nahi samja muje and please quote me as to get notification,please help me Cat a week away 
@rushinmehta said:The crew of an 8 member rowing team is to be chosesn from 12 members, of which 3 must row on one side and 2 must row on another side only.Find the number of ways in arranging the crew with 4 members on each side.
a) 40,320.
b) 30,240.
c) 60,480.
d) 10,080.
e) none of this.
Arun Sharma P n C,LOD-II page no 526,Q 10.
Please explain me logic as ans ka logic nahi samja muje and please quote me as to get notification,please help me Cat a week away
7C1*6c2 4!4!=60480??
@Subhashdec2 said:7C1*6c2 4!4!=60480??
How????????
Same solution is given in Arun sharma,but How yaar explain me logic.
@rushinmehta said:How????????Same solution is given in Arun sharma,but How yaar explain me logic.
choose 1 from rest 7
choose 2 from the left 6
arrange on both sides 4!4!
choose 2 from the left 6
arrange on both sides 4!4!
which 7 ? and 6?
4! 4! is fine.
i got 2 know from solution 7C1 and 6C2 is arun sharma has choosen 1 from 7 and 2 from 6,please explain in brief,thanku in advance.
@Subhashdec2 said:choose 1 from rest 7 choose 2 from the left 6 arrange on both sides 4!4!
which 7 ? and 6?
4! 4! is fine.
i got 2 know from solution 7C1 and 6C2 is arun sharma has choosen 1 from 7 and 2 from 6,please explain in brief,thanku in advance.
@rushinmehta said:which 7 ? and 6?4! 4! is fine.i got 2 know from solution 7C1 and 6C2 is arun sharma has choosen 1 from 7 and 2 from 6,please explain in brief,thanku in advance.
12-3-2
the predefined ones
3 will row on side a 2 will row on side b
the predefined ones
3 will row on side a 2 will row on side b
Please help me in this one-
Number System
LOD 1 -Question 93
A boy took a seven digit number ending in 9 and raised it to an even power greater than 2000. He then took no 17 and raised it to a power which leaves rem 1 when divided by 4. If he multiplies both nos, wot wil be the unot digit of no hence obtained ?
My take -
9 raised to even power gives 1 in unit place
all powers of 17 leave rem 1 when divided by 4.
Cycle of 7 power is- 7, 9, 3 and 1
hence when both the nos r multiplied then unit digit = 1*7 or 1*9 or 1*3 or 1*1
thus ans is 7,9,3,1
but book gives ans as just 7 
please help !
@puja_twinkle Let the 1st number be ABCDEF9 . since the last digit is 9 and raising even power will give unit digit as 1.
for number 17 raising power 4n+1 will give unit digit as 7. since
cycle of 7 is
7
9
3
1
. since power= 4n+1 =1 i.e unit digit for 17^(4n+1) =7.
Multiplying 1*7 =7.
@puja_twinkle I think U r getting the question wrong. it says
" raised it to a power which leaves rem 1 when divided by 4 ".
that means, Power= 4n+1.
17^(4n+1)
for number 17 raising power 4n+1 will give unit digit as 7. since
cycle of 7 is
7
9
3
1
. since power= 4n+1 =1 i.e unit digit for 17^(4n+1) =7
cycle of 7 is
7
9
3
1
. since power= 4n+1 =1 i.e unit digit for 17^(4n+1) =7
Please help me in this one-
Number System
LOD 2 -Question 70
A triangular number is defined as a number which has the property of being expressed as a sum of consecutive natural nos starting with 1. hw many triangular nos less than 1000 hv the property that they r the diff of squares of two consecutive natural nos ?
the book lists odd triangular no like 3,15,21.......903 as the solution
but then even 7 can be expressed as 4+3 and as 4 square- 3 square.
and even 9 : 4+5=9 as well as 5 square - 4 square =9
why r these not a part of the solution ???
Number System
LOD 2 -Question 70
A triangular number is defined as a number which has the property of being expressed as a sum of consecutive natural nos starting with 1. hw many triangular nos less than 1000 hv the property that they r the diff of squares of two consecutive natural nos ?
the book lists odd triangular no like 3,15,21.......903 as the solution
but then even 7 can be expressed as 4+3 and as 4 square- 3 square.
and even 9 : 4+5=9 as well as 5 square - 4 square =9
why r these not a part of the solution ???
@puja_twinkle said:Please help me in this one-Number SystemLOD 2 -Question 70A triangular number is defined as a number which has the property of being expressed as a sum of consecutive natural nos starting with 1. hw many triangular nos less than 1000 hv the property that they r the diff of squares of two consecutive natural nos ?the book lists odd triangular no like 3,15,21.......903 as the solutionbut then even 7 can be expressed as 4+3 and as 4 square- 3 square.and even 9 : 4+5=9 as well as 5 square - 4 square =9why r these not a part of the solution ???
because 7 can't be expressed as the sum of 1+2+...
Facing prob in Averages chapt lod 2 question 1
With an average speed of 40km/h a train reaches its destination in time.. If it goes with an average speed of 35km/h it is late by 15mint..The length of the total journey is?????