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- Question
- An alloy of gold and silver weights 50g. It contains 80% gold. How much gold should be added to the alloy, so that percentage of gold is increased to 90?
Options- A. 50g
- B. 60g
- C. 30g
- D. 40g
- Correct Answer
- 50g
ExplanationGold in 50g of alloy = (80 x 50)/100 = 40 g
Let W gram gold must be added.
Now, according to the question,
(40 + W) / (50 + W) = 90/100
? 100( 40 + W) = 90 (50 + W)
? 10(40 + W) = 9 (50 + W)
? 400 + 10W = 450 + 9W
? W = 450 - 400
? W = 50g
Thus, 50 g of gold must be added to make it 90% - 1. 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
- 2. 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
- 3. 387 x 387 + 114 x 114 + 2 x 387 x 114 =?
Options- A. 250001
- B. 251001
- C. 260101
- D. 261001 Discuss
- 4. 3 pumps, working 8 hours a day, can empty a tank in 2 days. How many hours a day should 4 pumps work in order to empty the tank in 1 day?
Options- A. 10
- B. 12
- C. 8
- D. 15 Discuss
- 5. In how many different ways can the letters of word JUDGE be arranged so that the vowels always come together?
Options- A. 48
- B. 24
- C. 120
- D. 60 Discuss
- 6. A sum of money amounts to Rs. 850 in 3 years and Rs. 925 in 4 year. The sum is?
Options- A. Rs. 600
- B. Rs. 575
- C. Rs. 625
- D. Data inadequate Discuss
- 7. If the diameters of a circle is increased by 100% . Its area is increased by?
Options- A. 100%
- B. 200%
- C. 300%
- D. 400% Discuss
- 8. The traffic lights at three different road crossings changes after every 48 sec., 72 sec. and 108 sec. respectively. If they all change simultaneously at 8 : 20 : 00 hrs, then they will again change simultaneously at?
Options- A. 8 : 27 : 12 hrs.
- B. 8 : 27 : 24 hrs.
- C. 8 : 27 : 36 hrs.
- D. 8 : 27 : 48 hrs. Discuss
- 9. Average weight of 19 men is 74 kg and the average weight of 38 women is 63 kg. What is the average weight(rounded off to the nearest integer) of all the men and the women together.
Options- A. 59 kg
- B. 65 kg
- C. 69 kg
- D. 67 kg Discuss
- 10. Find the highest common factor of 36 and 84.
Options- A. 4
- B. 6
- C. 12
- D. 18 Discuss
More questions
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
Correct Answer: 251001
Explanation:
Given expression = a2+b2+2ab = (a+b)2
where a = 387 and b = 114
= (387 + 114 )2
= (501)2
=(500 +1 )2
=(500)2 + (1)2+ 2 x 500 x 1
= 250000 + 1 +1000 = 251001.
Correct Answer: 12
Explanation:
3 pumps, can empty a tank in 2 days by working 8 hours a day.
1 pumps, can empty a tank in 2 days by working 8 x 3 hours a day.
1 pumps, can empty a tank in 1 days by working 8 x 3 x 2hours a day.
4 pumps, can empty a tank in 1 days by working 8 x 3 x 2 / 4 hours a day.
4 pumps, can empty a tank in 1 days by working 2 x 3 x 2 hours a day.
4 pumps, can empty a tank in 1 days by working 12 hours a day.
Correct Answer: 48
Explanation:
Total number of letters = 5
Number of vowels = 2.
If we consider both vowel as a one letter then,
Required number = 4! 2! = 48.
Correct Answer: Rs. 625
Explanation:
S.I for 1 year = Rs. (925 - 850) = Rs. 75
S.I for 3 year = Rs. (75 x 3) = Rs. 225
? Sum = Rs. (850 - 225) = Rs. 625
Correct Answer: 300%
Explanation:
Original area = ?(d/2)2
= (?d2) / 4
New area = ?(2d/2)2
= ?d2
Increase in area = (?d2 - ?d2/4)
= 3?d2/4
? Required increase percent
= [(3?d2)/4 x 4/(?d2) x 100]%
= 300%
Correct Answer: 8 : 27 : 12 hrs.
Explanation:
Interval of changes = (L . C . M of 48, 72, 108) sec. = 432 sec.
So, the lights will simultaneously changes after every 432 seconds i,e 7 min. 12 sec.
So, the next simultaneously changes will take place at 8 : 27 : 12 hrs.
Correct Answer: 67 kg
Explanation:
Here n1 = 19, a1 = 74, n2 = 38, a1 = 63
Total average weight = (n1a1 + n2 a2) / (n1 + n2)
= [(19) (74) + (38) (63)] / (19 + 38)
= 3800/57 ? 67 kg
Correct Answer: 12
Explanation:
36 = 2 2 x 3 2
84 = 22 x 3 x 7
∴ H.C.F. = 22 x 3 = 12.
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