Total no. of methods for selecting 2 letters out of 4 which has to be posted correctly = 4*3/2*1 = 6
No. of methods in which remaining 2 letters are posted wrongly is 1 only.
Hence total methods = 6*1 = 6
Let the numbers are x and y
According to the given conditions
(1/x) + (1/y) = 0.45
And (1/x2) + (1/y2) = 0.1025
On solving these two equations , we get the two values 4 and 5
No. of methods for selecting 6 cards out of 52 are 52*51*50*49*48*47/6*5*4*3*2*1
Similarly no. of methods for selecting 2 cards out of 48 after selecting 4 kings are
48*47/2*1
Hence probability is (48*47/2*1)/( 52*51*50*49*48*47/6*5*4*3*2*1)
= 3/54145
6 boys and 8 men get a total wage of Rs 8000 in 4 days. 8 boys and 6 men get a total of Rs 6000 in 3 days.
The efficiency ratio of boy and a man respectively?
The upper and lower part radius of a bucket is 30 cm. and 20 cm. Its height is 60 cm.
How much water can be filled in the bucket ?
It is given that: 1 litre = 1000 cm.^3
On increasing the slant sides of the bucket, a cone can be obtained, whose height is obtained by the formula h/(h-60) = 30/20
On solving h = 180
Think that: two cones can be formed by increasing the slant height, their radii and heights are 30 cm.,
20 cm. and 180 cm., 120 cm.
Volume of the cone is πr^2/3
Therefore volume of the bucket is π(30)^2*180/3 – π(20)^2*120/3
= 38000π cm.^3
= 38π litre
Original price of the object = 95/1.2
On selling the object in 75 rupee amount received = 75/(95/1.2)
= 94.74 %
Hence % loss = (100 – 94.74) % = 5.26 %
"The gaming of numbers is called maths.So participate in this wonderful game and explore in it,learn in it and enjoy in it.Then only you can pass in this wonderful game."
Kumar Purnendu
" To love Math is to embrace understanding.To use math is embrace life and its complexities."