In a class of 35 students, the girls strength is 2/5 of the boys strength, how many boys & girls are there?
961456
assume b=boys ; g=gals\n\ng = (2/5)b\n \nb+(2/5)b =35\n(7/5)b=35\nb=25\n\nso , g=10 ; b=25
233027
There are 8! different arrangements (permutations) of the 8 friends.\n\nThere are 4! different arrangements of the 4 boys.\n\nThere are 5 different locations where the leftmost boy can sit when the 4 boys sit together.\n\nTherefore, there are 5*4! (or 5!) arrangements of the boys where all the boys sit together.  But there are also 4! arrangements of the 4 girls in the remaining slots.  So there are 5!*4! arrangements where the 4 boys sit together.\n\nSince there are 8! arrangements overall, the probability of all boys sitting together is (5!*4!)/8!.\n\nSimilarly, if the boys sit to the left and the girls sit to the right, then the probability is (4!*4!)/8!.\n\nInterestingly, this last answer is also the same probability as boy-girl-boy-girl-boy-girl-boy-girl and also the probability of girl-boy-girl-boy-girl-boy-girl-boy.  Therefore, the probability of alternating seats is (2*4!*4!)/8!.\n\nRecall that n! (read n-factorial) is n*(n-1)*(n-2)*...*3*2*1.
197902
teachers to pupil ratio is 3:8\n\nlet the number of teachers be x and number of pupil be y\ntherefore x/y=3/8 and y=8x/3 \n\nif 12 pupils left then y-12 pupils remain while the number of teachers are the same subsituting in terms of x then new no of pupils is (8x/3)-12 i;e (8x-36)/3\n\nand the new  ratio is\n\n2:5 then 2/5= 3x/(8x-36) by cross multiplication becomes\n\n16x-72=15x therefore 16x-15x=72 and x=72 i.e no of teachers is 72 and subsituting for x in the above equation gives no. of pupils as (72*8-36)/3=180 pupils left in the hall\n\ntotal no. of people in the hall before the pupils left i.e. at first are (72+180+12)=264
182775
there are 6 place for 15 student so:-\n\n15*14*13*12*11*10=answer\n\nor simply use combination since the arrangement is not important\n\n15C6
984707
c = ( 18a + 19b ) / 37\n\nThere are 37 students in the class (18 boys, 19 girls), and the total points received are 18a (18 times the average score a for boys) plus 19b (19 times the average score b for girls).\n\nSo to determine c, the entire class average, you take all the scores together and divide by the number of students.  Therefore:\n\nc = (18a+19b) ÷ 37\n\nHope that helped!\n\n~ ♥ ~
34299
boys are more stronger than girls......but on kicking i think girls can stretch their legs better and farther than boys
842155
5 in girls\n6 in boys
194085
In the experiment of choosing a committee of 6 from a group of 8 women and 7 men,\n\nTotal no. of possible choices \n= no. of ways in which the 6 members of the committee can be chosen from the total 15\n==> n = C(15,6)\n==> n = 15*14*13*12*11*10/6*5*4*3*2*1\n==> n = 7*13*11*5\n==> n = 5005\n\nLet "A" be the event of choosing the committee with 3 women and 3 men\n\nFor Event "A"\n\n---------- Men----Women---Total\nAvailable---8-------7------15\nTo Choose---3-------3-------6\nChoices----C(8,3)-C(7,3)--C(15,6)\n\nNo. of favorable choices\n= (no. of ways in which the 3 men can be chosen from the total 8) * (no. of ways in which the 3 wommen can be chosen from the total 7) \n==> m(a) = C(8,3) * C(7,3)\n==> m(a) = 8*7*6/3*2*1 * 7*6*5/3*2*1\n==> m(a) = 8*7 * 7*5\n==> m(a) = 1960\n\nProbabilty of choosing the committe with 3 women and 3 men \n==> Probability of occurance of event "A" = m(a)/n\n==> P(A) = 1960/5005\n==> P(A) = 392/1001\n\n\nhttp://www.futureaccountant.com/probability/study-notes/\n\nhttp://www.schoolingkids.com/
527572
you got the right answer already.\n\nit's 50%.  Doesn't matter if you have 75 girls, it's still 50% chance that the next one will be a boy.
302535
There are 20 students who like both subjects...\n\n22 like Math only\n21 like English only\n20 like both Math and English\n30 don't like either subject\n----\n93 total students
516371
6 Boys, 2 girls\n(Donna has 6 brothers and 1 sister, Tom has 2 sisters and 5 brothers\n\n(Donna +1, Tom +5)
782327
whoa... there are about 750 students in my school... about 180 in the 10th grade... :-)
16819
think about boys and girls
744327
If the probability of haveng either a boy or a girl is equal, then the ration of boys to girls will be 1:1
391230
About 1/2 of them. The other 1/2 are the kids they bullied.
930557
Either we have BBBGGG or GGGBBB. In both cases, there are 3! ways of arranging boys, and 3! ways of arranging girls. So 3!*3!*2 = 72.
298927
there are (2/5)*30=12 boys.  Therefore, there are 30-12=18 girls.  The boy-girl ratio is 12:18 or 2:3.