Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 6)
6.
If 6 men and 8 boys can do a piece of work in 10 days while 26 men and 48 boys can do the same in 2 days, the time taken by 15 men and 20 boys in doing the same type of work will be:
Answer: Option
Explanation:
Let 1 man's 1 day's work = x and 1 boy's 1 day's work = y.
| Then, 6x + 8y = | 1 | and 26x + 48y = | 1 | . |
| 10 | 2 |
| Solving these two equations, we get : x = | 1 | and y = | 1 | . |
| 100 | 200 |
| (15 men + 20 boy)'s 1 day's work = |  |
15 | + | 20 |  |
= | 1 | . |
| 100 | 200 | 4 |
15 men and 20 boys can do the work in 4 days.
Discussion:
202 comments Page 11 of 21.
Prem kumar said:
9 years ago
Firstly I make an equation.
6men + 8boy =1/10---------> eq1.
26men + 48boy =1/2--------> eq2.
For eq1.
6men + 8boy =1/10.
We take common.
2 (3m + 4b) =1/10.
3m + 4b = 1/20.
Then,
Multiply the common value 5.
5* (3m + 4b) = 1/20*5.
Solve the equation.
15m + 20b = 1/4.
Now answer is 4 days.
6men + 8boy =1/10---------> eq1.
26men + 48boy =1/2--------> eq2.
For eq1.
6men + 8boy =1/10.
We take common.
2 (3m + 4b) =1/10.
3m + 4b = 1/20.
Then,
Multiply the common value 5.
5* (3m + 4b) = 1/20*5.
Solve the equation.
15m + 20b = 1/4.
Now answer is 4 days.
Srujan said:
9 years ago
If you practice well this would be a short cut.
(6Men + 8Boy).10 = (26Men + 48Boy).2.
=> (6Men + 8Boy).5 = (26Men + 48Boy).1.
30m => 48B
26m =>40B
------------------
4m = 8B
1Men = 2Boy
15Men + 20Boy = 25Men
6men + 4men = (1men = 2Boy)
10men --> 10days
25men---?
So,
10*10 = 25*D
D = 4days.
25men = 15men + 20boy = 4days.
(6Men + 8Boy).10 = (26Men + 48Boy).2.
=> (6Men + 8Boy).5 = (26Men + 48Boy).1.
30m => 48B
26m =>40B
------------------
4m = 8B
1Men = 2Boy
15Men + 20Boy = 25Men
6men + 4men = (1men = 2Boy)
10men --> 10days
25men---?
So,
10*10 = 25*D
D = 4days.
25men = 15men + 20boy = 4days.
Swati said:
9 years ago
You are genius @Siddharth.
Varuni said:
10 years ago
Because their one day work will be 1\10.
While the total number of days to do the work = 10.
Solution :
2x + 3y = 1/10.
3x +2y = 1/8.
20x + 30y = 1.
24x + 16y = 1.
120x + 180y = 6.
120x + 80y = 5.
100y = 1.
y = 1/100.
x = 7/200.
While the total number of days to do the work = 10.
Solution :
2x + 3y = 1/10.
3x +2y = 1/8.
20x + 30y = 1.
24x + 16y = 1.
120x + 180y = 6.
120x + 80y = 5.
100y = 1.
y = 1/100.
x = 7/200.
Aditi said:
10 years ago
Can you tell why we have taken 1/10 days in the above question's equation?
Viki said:
10 years ago
I'm too confused. Please give me shortcut method.
Poorva said:
10 years ago
3 men and 2 boys can complete a work in 16 days, while 2 men and 3 boys complete same work in 20 days. Then how much days will it takes to complete the same work with 2 men and 1 boy (work and time question from arihant book).
Chinna said:
10 years ago
Sir please give a shortcut technique.
Renju K S said:
10 years ago
@Meera.
Can you explain how you got 3/5 in RHS by multiplying with 6 to the 1st equation?
Can you explain how you got 3/5 in RHS by multiplying with 6 to the 1st equation?
Naresh said:
10 years ago
2x+3y = 1/10 ----- (1).
3x+2y = 1/8 ------ (2).
2x+1y = ? ------- (3).
Answer: 12 1/2.
Is it right?
3x+2y = 1/8 ------ (2).
2x+1y = ? ------- (3).
Answer: 12 1/2.
Is it right?
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