X can do a work in 10 days and Y in 15 days. If they work on it together for 3 days, then the fraction of the work that is left is-
A
1/3 part
B
1/2 part
C
3/4 part
D
1/4 part
উত্তরের বিবরণ
Question: X can do a work in 10 days and Y in 15 days. If they work on it together for 3 days, then the fraction of the work that is left is-
Solution:
X's 1 day's work = 1/10
Y's 1 day's work = 1/15
∴ (X + Y)'s 1 day's work = (1/10) + (1/15) part
= (3 + 2)/30 part
= 5/30
= 1/6 part
∴ (X + Y)'s 3 day's work = (1/6) × 3) part
= 1/2 part
Therefore, Remaining work = 1 - (1/2) = 1/2 part
0
Updated: 2 weeks ago
15 workers can build 45 chairs working 6 hours per day. How many extra workers are required to produce 60 chairs working 4 hours per day?
Created: 1 week ago
A
0 workers
B
10 workers
C
12 workers
D
15 workers
Question: 15 workers can build 45 chairs working 6 hours per day. How many extra workers are required to produce 60 chairs working 4 hours per day?
Solution:
6 ঘণ্টা কাজ করে 45টি চেয়ার তৈরি করে 15 জন শ্রমিক
1 ঘণ্টা কাজ করে 1টি চেয়ার তৈরি করে = (15 × 6) /45 জন শ্রমিক
4 ঘণ্টা কাজ করে 60টি চেয়ার তৈরি করে = (15 × 6 × 60)/(45 × 4) জন শ্রমিক
= 30 জন
∴ অতিরিক্ত শ্রমিকের সংখ্যা = 30 - 15 = 15 জন
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
A takes three times as much time as B or twice as much time as C to finish a piece of work. Working together, they can finish the work in 3 days. B can do the work alone in how many days?
Created: 1 week ago
A
14 days
B
8 days
C
6 days
D
10 days
Question: A takes three times as much time as B or twice as much time as C to finish a piece of work. Working together, they can finish the work in 3 days. B can do the work alone in how many days?
Solution:
ধরা যাক,
A, B ও C যথাক্রমে কাজটি শেষ করতে সময় লাগে x, x/3, এবং x/2 দিন।
তারা একসাথে ৩ দিনে কাজ শেষ করে।
অর্থাৎ তাদের একদিনের কাজ হলো 1/3।
∴ A + B + C এর একদিনের কাজ = (1/x) + (3/x) + (2/x)
= (1 + 3 + 2)/x
= 6/x
এখন,
6/x = 1/3
∴ x = 18
∴ B একা কাজ শেষ করতে সময় নেবে = 18/3 = 6 দিন।
0
Updated: 1 week ago
