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### Mathmetics

ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams

##### The weights of two persons A and B are in the ratio of 4 : 5. The weight of 'A' increases by 10% and the total weight of A and B together becomes 82.8 kg, with an overall increase of 15%. By what per cent did the weight of B increase ?
 1) 12.5% 2) 17.5% 3) 19% 4) 21% 5) None of these
Explanation : Allegation Method:

10%  (C)                        x%  (D)

15% (M)

(D-M) = x-15                 (M-C) = 15 -10=5

So, x-15 / 5 = 4/5
or x =15+4= 19%

##### When in each box 6 or 8 dozens of oranges were packed, five dozens were remaining. Therefore, bigger boxes were taken to pack 9 or 10 dozens of oranges. However still five dozens of oranges remains. What was the least number of dozens of oranges to be packed ?
 1) 288 2) 360 3) 365 4) 435 5) None of these
Explanation : LCM of 6,8,9 and 10 is 360.
So, total numbers of dozens of oranges are 360 +5 = 365
##### There are 408 boys and 312 girls in a school which are to be divided into equal sections of either boys or girls alone. what should be the total number of sections thus formed ?
 1) 30 2) 31 3) 32 4) 35 5) None of these
Explanation : HCF of 408 and 312 is 24.
So, total numbers of sections = (408+312) /24  = 30
##### What are the two natural numbers whose difference is 66 and the LCM is 360 ?
 1) 90 and 24 2) 120 and 24 3) 120 and 54 4) 180 and 114 5) None of these
Explanation : The factors of 360 = 2 X 2 X 2 X 3 X 3 X 5
So, two numbers are 2 X 2 X 2 X 3 =24 and 2 X 3 X 3 X 5 = 90
##### A shopkeeper sells some articles on profit of 20% of the cost price. Find out the actual Gain ? I. Selling price of the article. II. Cost price of the article
 1) Neither I nor II 2) Either I or II 3) Both I and II 4) Only II 5) Only I
Answer : Either I or II
##### If x=2015, y=2014 and 2013 , then x2+y2+z2 -xy-yz-zx = ?
 1) 2 2) 3 3) 4 4) 6 5) None of these
Explanation : ATQ: x2+y2+z2 -xy-yz-zx
= x2-xy+y2 -yz+z2-zx
x(x-y) + y((y-z) + z(z-x)
= 2015(2015-2014) + 2014(2014-2013)+2013(2013-2015)
= 2015 + 2014 + 4026
=4029-4026 =3

##### Directions:In each of the following questions a number series is given. After the series a number is given followed by (a),(b),(c),(d)&(e).Yoy have to complete the series starting with the number given, following the sequence of the given series, and answer the questions given below the series.(A) 4 2 3 7.5 26.25 118.125(B) 6 (a) (b) (c) (d) (e)What will come in the place of (c) ?
 1) 12.25 2) 11.5 3) 11.125 4) 12.5 5) None of these
Explanation : x .5, x1.5, x 2.5, x 3.5 , x 4.5 and so on
##### Directions:In each of the following questions a number series is given. After the series a number is given followed by (a),(b),(c),(d)&(e).Yoy have to complete the series starting with the number given, following the sequence of the given series, and answer the questions given below the series.(A) 2 3 7 25 121 721 (B) 3 (a) (b) (c) (d) (e)What will come in the place of (c) ?
 1) 31 2) 39 3) 45 4) 49 5) None of these
Explanation : x 2 -1, x 3-2, x 4-3, x 5 -4 and so on ...