Hasan can dig 18 holes in 12 minutes. Faruk can dig the same number of holes in only 6 minutes. Hasan digs the first 9 holes, then Faruk digs for 2 minutes, and finally Hasan finishes the remaining holes. How long will it take them to dig 27 holes in total?
A
10 minutes
B
16 minutes
C
18 minutes
D
21 minutes
উত্তরের বিবরণ
Question: Hasan can dig 18 holes in 12 minutes. Faruk can dig the same number of holes in only 6 minutes. Hasan digs the first 9 holes, then Faruk digs for 2 minutes, and finally Hasan finishes the remaining holes. How long will it take them to dig 27 holes in total?
Solution:
Faruk can dig 18 holes in 6 minutes.
∴ In 2 minutes, he can dig = (18 × 2)/6 holes
= 6 holes
Hasan first digs 9 holes.
∴ Total completed = 9 (Hasan) + 6 (Faruk) = 15 holes
Remaining = 27 - 15 = 12 holes
Hasan can dig 18 holes in 12 minutes.
∴ To dig 12 holes, Hasan will take = (12 × 12) / 18 = 8 minutes
Time Hasan spent digging first 9 holes = (12 × 9)/18 = 6 minutes
∴ Total time = 6 (Hasan) + 2 (Faruk) + 8 (Hasan) = 16 minutes
0
Updated: 1 week ago
X can complete a work in 12 days, and Y alone can do it in 18 days. They work together for 6 days, and Z completes the remaining work in 3 days. If the total payment for the work is Tk. 600, how much should Z get?
Created: 1 week ago
A
Tk. 75
B
Tk. 90
C
Tk. 100
D
Tk. 120
Question: X can complete a work in 12 days, and Y alone can do it in 18 days. They work together for 6 days, and Z completes the remaining work in 3 days. If the total payment for the work is Tk. 600, how much should Z get?
সমাধান:
X-এর একদিনের কাজ = 1/12
Y-এর একদিনের কাজ = 1/18
X ও Y একসাথে ৬ দিন কাজ করে:
= 6 × (1/12 + 1/18)
= 6 × {(3 + 2)/36} = 6 × (5/36) = 30/36 = 5/6
∴ বাকি কাজ = 1 − 5/6 = 1/6
Z এই 1/6 কাজ ৩ দিনে করেছে, অর্থাৎ Z-এর কাজ = 1/6
X-এর কাজ = 6 × 1/12 = 1/2
Y-এর কাজ = 6 × 1/18 = 1/3
Z-এর কাজ = 1/6
তাহলে অনুপাত = 1/2 : 1/3 : 1/6
= 3 : 2 : 1
মোট টাকা = 600
Z-এর অংশ = 1/(3+2+1) = 1/6
∴ Z পাবে = 600 × (1/6) = 100 টাকা
0
Updated: 1 week ago
John can paint 60 walls in 20 minutes. Emma can paint 9 walls in 15 minutes. Working together, how many walls can they paint in 25 minutes?
Created: 2 weeks ago
A
65 walls
B
90 walls
C
75 walls
D
95 walls
Question: John can paint 60 walls in 20 minutes. Emma can paint 9 walls in 15 minutes. Working together, how many walls can they paint in 25 minutes?
Solution:
John can paint in 1 min = 60/20 = 3 walls
Emma can paint in 1 min = 9/15 = 3/5 walls
∴ Working together they can paint in 1 min = (3 + 3/5) = 18/5 walls
∴ They can paint in 25 min = (18 × 25)/5 = 90 walls
So John and Emma can paint 90 walls together in 25 minutes.
0
Updated: 2 weeks ago
30 workers can build 60 machines working 4 hours per day. How many extra workers are required to produce 90 machines working 6 hours per day?
Created: 2 weeks ago
A
0 workers
B
10 workers
C
20 workers
D
15 workers
Question: 30 workers can build 60 machines working 4 hours per day. How many extra workers are required to produce 90 machines working 6 hours per day?
Solution:
4 hours to build 60 machines by 30 workers
1 hour to build 1 machine by = (30 × 4)/60 workers
6 hours to build 90 machines by = (2 × 90)/6 workers
= 30 workers
∴ extra workers = (30 - 30) = 0 workers
0
Updated: 2 weeks ago
