1.seven different objects must be divided among 3 persons. In how many ways this can be done if atleast one of them gets exactly one object?
2.In how many ways can we distribute 10 different pencils to 3 students?
3.a cicler circumscribes three unit circles that touch each other. What is the area of the larger cirlce?

• 1: (7-1)c(3-1)=15 because atleast one object gets one person
  2: 3^10
• 11 years agoHelpfull: Yes(8) No(16)
• 1)1176 is the answer
• 11 years agoHelpfull: Yes(6) No(1)
• 3:the radius of unit circle is 1. when we take 3 circles and join their radius we get an equilateral triangle of side 2.a circle circumscribes these 3 circles then
  we have abc/4R= root3 a^2/4
  where a=b=c=2 then we get R=2/root 3
  radius =pie r^2 = pie(R+1)^2
• 11 years agoHelpfull: Yes(4) No(1)
• formula:
  pie(2/root3 +1)^2
• 11 years agoHelpfull: Yes(3) No(0)
• 3. let r= radius of larger circle
  x= distance between centers of inner and outer circle
  so, x+r= radius of outer circle
  the inner circle centers form equilateral triangle
  equilateral triangle can be divided into 3 smaller isosceles triangles with side lengths 2r, x, and x. The angle at the centre of larger triangle (and at centre of larger circle) is 360/3 = 120
  
  Using law of cosines, we get:
  (2r)² = x² + x² - 2(x)(x) cos(120)
  4r² = 2x² - 2x² * (-1/2)
  4r² = 2x² + x² = 3x²
  x² = 4/3 r²
  x = 2/√3 r
  area of larger circle = pi(x+r)^2
  pi*((2/sqrt(3))*1+1)^2
• 11 years agoHelpfull: Yes(3) No(0)
• 1.12 ways
  2.36 ways
  
• 11 years agoHelpfull: Yes(2) No(5)
• 1.(7-1)C(3-2)=6C2=15 WAYS
  2.3^10
• 11 years agoHelpfull: Yes(1) No(0)
• 1. 7c1 * 6c2 * 5c3 = 7*15*10 = 1050
• 11 years agoHelpfull: Yes(0) No(6)
• @divya pls explain
  
• 11 years agoHelpfull: Yes(0) No(0)
• Division of m+n+p objects into three groups is given by (m+n+p)!m!×n!×p!
  But 7 = 1 + 3 + 3 or 1 + 2 + 4 or 1 + 1 + 5
  So The number of ways are (7)!1!×3!×3!×12! + (7)!1!×2!×4! + (7)!1!×1!×5!×12! = 70 + 105 + 21 = 196
• 10 years agoHelpfull: Yes(0) No(1)
• love masta.......calculation karne ke bad 196 kaise aa raha hai
• 9 years agoHelpfull: Yes(0) No(0)