Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q31. |
|
1) | 2 | 2) | 4 |
3) | 5 | 4) | 6 |
Answer : 8
Explanation :
Explanation :
Bag X:
Two balls taken from bag x, total probability,
According to the question,
40/87 = (Probability of getting 1st green and second blue * Probability of getting 1st blue and second green)
Take green = 10 and blue = 20
According to the question,
40/87 = 10 * 20 * 2/(30 * 29)
40/87 = 40/87
Let us take number of green balls taken out from bag Y be a
Number of blue balls taken out from bag Y = a + 4
According to the question,
(10 + a)C2/(30 + 2a + 4)C2 = 13/123
(10 + a) * (9 + a)/[(34 + 2a) * (33 + 2a)] = 13/123
Simplify the equation we get, a = 4
Number of blue balls taken out from bag Y = a + 4 = 4 + 4 = 8

Q32. |
|
1) | 10 | 2) | 20 |
3) | 29 | 4) | 30 |
Answer : 30
Explanation :
Explanation :
Bag X:
Two balls taken from bag x, total probability,
According to the question,
40/87 = (Probability of getting 1st green and second blue * Probability of getting 1st blue and
second green)
Take green = 10 and blue = 20
According to the question,
40/87 = 10 * 20 * 2/(30 * 29)
40/87 = 40/87
This satisfies the given condition.
So, total number balls in box X should be 30.

Q33. |
|
1) | 2/29 | 2) | 3/29 |
3) | 4/29 | 4) | 5/29 |
Answer : 3/29
Explanation :
Explanation :
Bag X:
Two balls taken from bag x, total probability,
According to the question,
40/87 = (Probability of getting 1st green and second blue * Probability of getting 1st blue and second green)
Take green = 10 and blue = 20
According to the question,
40/87 = 10 * 20 * 2/(30 * 29) or 40/87 = 40/87
This satisfies the given condition.
Probability of both green ball (A) = 10C2/30C2
= (10 * 9)/(29 * 30) = 3/29

Q34. |
Direction: Data below represent the number of people required for various projects to be completed in various days: Project Situation 1 Situation 2 Number of workers Days required Number of workers Days required A X 88 X+8 66 B Y Y-1 Y+6 Y-6 C Z2 75 M2 108 |
1) | 60 days | 2) | 80 days |
3) | 90 days | 4) | 120 days |
5) | None of these |
Answer : 90 days
Explanation : Total workers = 0.5Z * 2 M = 0.5 * (1.2 M) * 2 M = 1.2 M2 Total work = M2 * 108 = 1.2 M2 * No of days = > No of days = (M2 * 108) / (1.2 M2 ) = 90 days
Explanation : Total workers = 0.5Z * 2 M = 0.5 * (1.2 M) * 2 M = 1.2 M2 Total work = M2 * 108 = 1.2 M2 * No of days = > No of days = (M2 * 108) / (1.2 M2 ) = 90 days

Q35. |
|
1) | 33 days | 2) | 22 days |
3) | 36 days | 4) | 44 days |
5) | None of the |
Answer : 33 days
Explanation :
M1 * D1 = M2 * D2
Explanation :
Solutions:
Project A:
X * 88 = (X + 8) * 66
= > 88X = 66X + 8 * 66 = > 22X = 8 * 66 = > X = 24
Project B:
Y * (Y - 1) = (Y + 6) * (Y - 6)
Y2 – Y = Y2 – 62
= > Y = 36
Project C:
Z2 * 75 = M2 * 108
= > Z2 / M2 = 108/75
= > Z2 / M2 = 36/25
= > Z / M = 6/5
= > Z = 6/5 * M
= > Z = 1.2 M
24 * 88 = 64 * D2
= > D2 = (24 * 88)/64
= > D2 = 33 days

Q36. |
|
1) | 40 | 2) | 42 |
3) | 45 | 4) | 48 |
Answer : 45

Q37. |
|
1) | I and II together | 2) | Only II |
3) | I and II together | 4) | I and either II or III |
5) | Any two statements together. |
Answer : Any two statements together.
Explanation : Explanations : Let speed of boat in sill water be x kmph and velocity of stream be y kmph respectively.
Explanation : Explanations : Let speed of boat in sill water be x kmph and velocity of stream be y kmph respectively.
So, from I , we get x+y = 5kmph
From II, it given y = 2x/3 , we get x = 3kmph and y = 2kmph
From III, w get, x - y = 2.5 kmph
Therefore, to find out the speed of the boat any two statements together is sufficient.

Q38. | A rectangular container, whose base is square of side 15cm,stands on a horizontal table and holds water up to 3cm from the top. When a cube is placed in the water and is completely submerged, the water rises to the top and 54cm^3 of water overflows. What is its surface area? |
1) | 448cm2 | 2) | 464cm2 |
3) | 486cm2 | 4) | 524cm2 |
5) | None of these |
Answer : 486cm2

Q39. | The length of a rectangle increases by 20% and also its breadth increases by 15% . What should be the percentage change in its perimeter? |
1) | 35% | 2) | 36% |
3) | 38% | 4) | Can't be determined |
5) | None of these |
Answer : Can't be determined

Q40. | A is 25% more efficient than B and 50% more efficient than C. A and B together can complete a work in 20 days. How many days the same work can be completed by B and C if both work in alternate days and B starts the work first ? |
1) | 48 days | 2) | 49 days |
3) | 50 days | 4) | 51 days |
5) | None of these |
Answer : 49 days
