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- Question
- In a two-digit number, the digit at the unit's place is 1 less than twice the digit at the ten's place. If the digits at unit's and ten's place are interchanged, the difference between the new and the original number is less than the original number by 20. The original number is
Options- A. 47
- B. 59
- C. 23
- D. 35
- Correct Answer
- 47
Explanationlet us assume the ten's digit number be x and unit's place digit be y.
Then two digit Original Number = 10x + y
According to question ? y = 2x - 1 ................(1)
When digits are interchanged then new number = 10y + x
If the digits at unit's and ten's place are interchanged, the difference between the new and the original number is less than the original number by 20,
New Number - Original Number = Original number - 20
? 10y + x - (10x + y) = 10x + y - 20
? 10y + x - 10x - y - 10x - y = - 20
? 8y - 19x = - 20
? 19x - 8y = 20 ...................(2)
Put the value of y from equation (1) in above equation (2).
? 19x - 8(2x - 1) = 20
? 19x - 16x - 8 = 20
? 7x = 20 + 8
? 7x = 28
? x = 28/7
? x = 4
Put the value of y in equation (1)
From (i) y = 2 x 4 -1 = y = 7
? original number = 10x + y =10 x 4 + 7 = 47. - 1. A and B together can complete a work in 3 days. They started together but after 2 days, B left the work. If the work is completed after 2 more days, B alone could do the work in how many days?
Options- A. 5
- B. 6
- C. 7
- D. 10 Discuss
- 2. A wheel makes 1000 revolutions in covering a distance of 88 km. the diameter of the wheel is?
Options- A. 24 meters
- B. 40 meters
- C. 28 meters
- D. 14 meters Discuss
- 3. 25, 36, 49, 81, 121, 169, 225
Options- A. 36
- B. 49
- C. 121
- D. 169 Discuss
- 4. (.896 x .752 +.896 x .248) / (.7 x .034 + .7 x.966) =?
Options- A. 1.28
- B. 0.976
- C. 12.8
- D. 9.76 Discuss
- 5. Einstein goes from Ahmedabad To Lucknow at the speed of 40 km/hr and returned at the speed of 60 km/hr .the average speed of Einstein during the whole journey is
Options- A. 48 km/hr
- B. 24 km/hr
- C. 50 km/hr
- D. none of these Discuss
- 6. Today is Monday. After 61 days, it will be
Options- A. Wednesday
- B. Saturday
- C. Tuesday
- D. Thursday Discuss
- 7. 9548 + 7314 = 8362 + (?)
Options- A. 8230
- B. 8410
- C. 8500
- D. 8600
- E. None of these Discuss
- 8. The true discount on a certain sum due 1 yr hence at 30% per annum, is ? 240. What is the banker' discount on the same sum for the same time and at the same rate?
Options- A. ? 400
- B. ? 212
- C. ? 312
- D. ? 445 Discuss
- 9. Calendar of month July is same as that of which month of previous year.
Options- A. May
- B. September
- C. April
- D. None of these Discuss
- 10. A coin is successively tossed two times. Find the probability of getting? (1) exactly one head (2)at least one head
Options- A. 1/2 , 3/4
- B. 2/3, 1/4
- C. 1/4, 4/5
- D. 1/2, 2/3 Discuss
More questions
Correct Answer: 6
Explanation:
(A + B)'s 2 day's work = 2 x (1/3) = 2/3
Remaining work = 1 - (2/3) = 1/3
A will complete 1/3 work in 2
A will complete 1 work in 6
A's 1 days work = 1/6
B's 1 day's work = (1/3) - (1/6) = 1/6
? B will take 6 days to complete the work alone.
Correct Answer: 28 meters
Explanation:
Distance covered in one revolution = total distance travelled / total number of revolution.
= ( 88 x 1000) / 1000 m
= 88 m
We know that the distance covered in one revolution = circumference of the wheel.
? ?d = 88
? 22d / 7 = 88
? d = 28 m
Correct Answer: 36
Explanation:
So, 36 is wrong.
Correct Answer: 1.28
Explanation:
Given expression = (.896 x .752 +.896 x .248) / (.7 x .034 + .7 x.966)
=.[896 x (.752+.248)] / [.7 x (.034+.966)]
= .(896 x 1) / ( .700 x 1)
=896/700
= 1.28
Correct Answer: 48 km/hr
Explanation:
Average speed =2 x 40 x 60 / ( 40+ 60)
= 4800 / 100
= 48 km/hr
Correct Answer: Saturday
Explanation:
Each day of the week is repeated after 7 days.
So, after 63 days, it will be Monday.
After 61 days, it will be Saturday.
Correct Answer: 8500
Explanation:
9548 16862 = 8362 + x + 7314 x = 16862 - 8362 ----- = 8500 16862 -----
Correct Answer: ? 312
Explanation:
We know that
BG = SI on TD = (240 x 30 x 1 x 1)/100
= ? 72
BG = BD - TD
? BD = BG + TD
= 72 + 240
= ? 312
Correct Answer: May
Explanation:
If previous year is leap year then calendar of May is similar to July
Correct Answer: 1/2 , 3/4
Explanation:
In tossing a coin 2 times the sample space is 4 i,e (H, H), (H, T), (T, H), (T, T)
(1) If A1 denotes exactly one head
then A1 = {(H, T) (T, H) }
So, P(A1 ) = 2/4 = 1/2
(2) If A denotes at least one head
then A = {(H, T) (T, H) (H, H)}
? A = {(H, T) (T, H) (H, H )}
? P(A) = 3/4
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