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- Question
- The average of 13 results is 60. If the average of first 7 result is 59 and that of last 7 results is 61, What will be the seventh result?
Options- A. 90
- B. 50
- C. 75
- D. 60
- Correct Answer
- 60
ExplanationAccording to the fundamental to the fundamental formula
Average(A)= Sum (S) / Number(N)
From the question 60 = S / 13
? S = 60 x 13 = 780
Sum of first seven result = 59 x 7 = 413
Sum of last seven result = 61 x 7 = 427
? 7th result = (Sum of first seven result) + (Sum of last seven results) - (Sum of all the results)
= (413 + 427 - 780 )
= (840 - 780)
= 60
NoteSum of first seven when added to the sum of last seven result, then repetition of 7th result takes place. - 1. A alone can do a piece of work in 8 days while B alone can do it in 10 days. If they together complete this work and get ? 900 as their remuneration, then find the share of both the persons.
Options- A. A = ? 800 and B = ? 100
- B. A = ? 500 and B = ? 400
- C. A = ? 600 and B = ? 300
- D. A = ? 300 and B = ? 600 Discuss
- 2. 0. 53
Options- A. 53 / 100
- B. 53 / 90
- C. 53 / 99
- D. 26 / 45 Discuss
- 3. If 0.75 : x :: 5 : 8, then x is equal to:
Options- A. 1.12
- B. 1.2
- C. 1.25
- D. 1.30 Discuss
- 4. Nine examiners can examine a certain number of answer books in 12 days by working 5 hours a day. How many hours in a day should 4 examiners work to examine twice the number of answer books in 30 days?
Options- A. 9
- B. 11
- C. 13
- D. 17 Discuss
- 5. Find the value of the expression 1 - 2 + 3 - 4 + 5 - 6 + 7 + .... upto 100 terms .?
Options- A. -150
- B. -60
- C. -100
- D. -50 Discuss
- 6. The angles of depression of two ships from the top of a light house are 45° and 30° towards east. if the ships are 200 m apart, find the height of the light house .
Options- A. 100 m
- B. 173 m
- C. 200 m
- D. 273 m Discuss
- 7. The probability that a person will hit a target in shooting practice is 0.3 . If he shoots 10 times. Then the probability of his shooting the target is?
Options- A. 1
- B. 1 - (0.7)10
- C. (0.7)10
- D. (0.3)10 Discuss
- 8. A fort had provision of food for 150 men for 45 days. After 10 days, 25 men left the fort. The number of days for which the remaining food will last, is:
Options- A. 39
- B. 37
- C. 42
- D. 56 Discuss
- 9. If m men working m h per day, can do m units of work in m days, then n men working n h per day would be able to complete how units of work in days?
Options- A. n3/m2
- B. m3/n2
- C. m4/n2
- D. n4/m3 Discuss
- 10. The average age of two boys and their father is greater then average age of those two boys and their mother by 3 yr. The average age of the four is 19 yr. If the average age of the two boys be 5 1/ 2, then find the age of the father and mother.
Options- A. 37 yr and 28 yr
- B. 47 yr and 38 yr
- C. 50 yr and 41 yr
- D. 35 yr and 32 yr Discuss
More questions
Correct Answer: A = ? 500 and B = ? 400
Explanation:
A' s 1 day's work = 1/8
B' s 1 day's work = 1/10
? A' s share : B' s share
= 1/8 : 1/10 = 5/40 : 4/40 = 5 : 4
Let A' s share = 5k
and B' s share = 4k.
According to the question,
5k + 4k = 900
? 9k = 900
? k = 100
? A' s share = 5k = 5 x 100 = ? 500
and B' s share = 4k = 4 x 100 = ? 400.
Correct Answer: 53 / 99
Explanation:
0.53 = 53 / 99
Correct Answer: 1.2
Explanation:
| (x x 5) = (0.75 x 8) ⟹ x = | ❨ | 6 | ❩ | = 1.20 |
| 5 |
Correct Answer: 9
Explanation:
Correct Answer: -50
Explanation:
(1 - 2) = -1
(3 - 4) = -1
(5 - 6) = -1
and so on.
? Total terms of -1 will be 50.
? Answer = -1 x 50 = -50
Correct Answer: 273 m
Explanation:
Let us draw a figure below as per given question.
Let AB = h meter be the height of the tower and two ships are situated at D and C respectively; such that, CD = 200 m; ?ADC = 30° ?ACB = 45° and BC = x meter (say)
Now from right triangle ABC,
tan 45° = h/x ? 1 = h/x
? x = h
Again from right triangle ABD,
tan 30° = h/( 200 + x )
? 1/?3 = h/( 200 + x )
Since x = h , we will get.
? 1/?3 = h/(200 + h )
? (200 + h ) = h X ?3
? h X ?3 - h = 200
? h x 1.732 - h = 200
? h(1.732 - 1) = 200
? h = 200/0.732 = 273.2 m = 273 m
Correct Answer: (0.3)10
Explanation:
? Probability in each trial (shooting) = 0.3
? Reqd. probability = (0.3)10
Correct Answer: 42
Explanation:
As per the given question ,
Food of 150 men for 45 days = 150 × 45 = 6750 unit
After 10 days , Food of 150 men for 150 × 10 = 1500 unit
And after 10 days remaining men = 150 - 25 = 125
and remaining food = 6750 - 1500 = 5250 unit
Let D be the number of days for which the remaining food .
So, 125 × D = 5250
? D = 5250 /125 = 42 days
Correct Answer: n3/m2
Explanation:
Let the required number of units of work = k
According to the formula,
W1= m and W2 = k
M1T1D1W2 = M2T2D2W1
? m x m x m x k = n x n x n x m
? x= (m x n3) / m3 = n3/m2
Correct Answer: 37 yr and 28 yr
Explanation:
Let the ages of mother, father and boys be M, F, B1 and B2, respectively.
The total age of four member
= 19 x 4
= 76 yr.
Given (B1 + B1)/2 = 11/2
? B1 + B2 = 11
M + F + B1 + B2 = 76 - 11
? M + F = 65 .......(i)
According to the question,
(B1 + B2 + F) / 3 = (B1 + B2 + M) / 3 + 3
? B1 + B2 + F) = B1 + B2 + M + 9
? F = M + 9
? F - M = 9 ............. (ii)
From Eqs (i) and (ii), we get
F = 37 yr and M = 28 yr
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