Rahim and Karim can finish a work together in 6 hours. If Rahim takes 3 times as long as Karim to finish the job alone, how long will Karim take to finish the job alone?
A
9 hours
B
8 hours
C
12 hours
D
15 hours
উত্তরের বিবরণ
Question: Rahim and Karim can finish a work together in 6 hours. If Rahim takes 3 times as long as Karim to finish the job alone, how long will Karim take to finish the job alone?
Solution:
ধরি, করিম একা কাজটি শেষ করতে সময় নেয় = x ঘন্টা
রহিম একা কাজটি শেষ করতে সময় নেয় = 3x ঘন্টা
এখন,
করিমের 1 ঘন্টার কাজের পরিমাণ = 1/x অংশ
রহিমের 1 ঘন্টার কাজের পরিমাণ = 1/(3x) অংশ
তারা একসাথে 1 ঘন্টায় কাজ করতে পারে = (1/x) + 1/(3x)
= (3+1)/(3x)
= 4/(3x) অংশ
একসাথে কাজটি শেষ করতে সময় লাগে = 6 ঘন্টা
অর্থাৎ, 6 ঘন্টায় তারা পুরো 1টি কাজ শেষ করে
তাহলে,
(4/3x) × 6 = 1
⇒ 24/(3x) = 1
⇒ 8/x = 1
⇒ x = 8
∴ করিমের কাজটি একা শেষ করতে 8 ঘন্টা সময় লাগবে।
0
Updated: 1 week ago
If 10 men or 18 women can do a work in 50 days then how many days would it take 25 men and 15 women to do twice the work?
Created: 2 weeks ago
A
25 days
B
30 days
C
32 days
D
40 days
Question: If 10 men or 18 women can do a work in 50 days then how many days would it take 25 men and 15 women to do twice the work?
Solution:
Here,
10 men = 18 women
∴ 1 men = 18/10 women
∴ 25 men = (18 × 25)/10 women
= 45 women
∴ 25 men and 15 women = (45 + 15) = 60 women
ATQ,
18 women can do the work in 50 days
∴ 1 women can do the work in = (50 × 18) days
∴ 60 women can do the work in (50 × 18)/60 days
= 15 days
Hence to do twice the work time need = (15 × 2) = 30 days
0
Updated: 2 weeks ago
A can complete a piece of work in 6 days working 8 hours a day, and B can complete the same work in 12 days working 8 hours a day. How long will it take them to complete the work together if they work 4 hours a day?
Created: 2 weeks ago
A
6 days
B
5 days
C
10 days
D
8 days
Question: A can complete a piece of work in 6 days working 8 hours a day, and B can complete the same work in 12 days working 8 hours a day. How long will it take them to complete the work together if they work 4 hours a day?
Solution:
A can complete the work in 8 × 6 = 48 hours
1 hour's work of A = 1/48 part
B can complete the work in 8 × 12 = 96 hours
1 hour's work of B = 1/96 part
(A + B)'s 1 hour's work = (1/48) + (1/96) part
= (2 + 1)/96 part
= 3/96 part
= 1/32
∴ Time taken by (A + B) working 4 hours daily = 32/(1 × 4)
= 8 days
0
Updated: 2 weeks ago
Rafi alone can complete a work in 10 days and Tareq alone can complete it in 15 days. Rafi and Tareq undertook to complete the work for Tk. 7500. With the help of Salman, they finished the work in 5 days. How much should Salman be paid?
Created: 1 week ago
A
Tk. 1200
B
Tk. 1250
C
Tk. 1300
D
Tk. 1380
Question: Rafi alone can complete a work in 10 days and Tareq alone can complete it in 15 days. Rafi and Tareq undertook to complete the work for Tk. 7500. With the help of Salman, they finished the work in 5 days. How much should Salman be paid?
Solution:
Rafi's 1 day work = 1/10
Tareq's 1 day work = 1/15
Rafi + Tareq + Salman's 1 day work = 1/5
∴ Salman's 1 day work = 1/5 - (1/10 + 1/15)
= (6 - 3 - 2)/30
= 1/30
Salman's 5 days work = 5 × 1/30 = 1/6
Salman completed 1/6 of the total work.
∴ He should be paid 1/6 of Tk. 7500
∴ Salman’s payment = 7500 × 1/6 = Tk. 1250
0
Updated: 1 week ago
