Two pipes, A and B, can fill a tank in 37.5 minutes and 45 minutes. If both pipes are open, after how many minutes should pipe B be closed to fill the tank in half an hour?
A
5 minutes
B
9 minutes
C
10 minutes
D
15 minutes
উত্তরের বিবরণ
Question: Two pipes, A and B, can fill a tank in 37.5 minutes and 45 minutes. If both pipes are open, after how many minutes should pipe B be closed to fill the tank in half an hour?
Solution:
নল A দ্বারা 37.5 মিনিটে পূর্ণ হয় 1 অংশ
∴ 1 মিনিটে পূর্ণ হয় = (1/37.5) অংশ
∴ 30 মিনিটে পূর্ণ হয় = 30/37.5 = 300/375 = 4/5 অংশ
∴ পূর্ণ হওয়ার বাকি থাকে = 1 - (4/5)
= (5 - 4)/5
= 1/5 অংশ
B নল দ্বারা ,
1 অংশ পূর্ণ হতে সময় লাগে = 45 মিনিট
∴ 1/5 অংশ পূর্ণ হতে সময় লাগে = 45 × (1/5) = 9 মিনিট
∴ B নলটি 9 মিনিট পর বন্ধ করলে ট্যাংকটি 30 মিনিটে পূর্ণ হবে।
Shortcut:
(30/37.5) + (x/45) = 1 (whole)
⇒ 0.8 + (x/45) = 1
⇒ x/45 = 1 - 0.8 = 0.2
⇒ x = 0.2 × 45 = 9
0
Updated: 1 day 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 month 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 month ago
Musa can do 1/4 of a work in 6 days. In how many days will he complete the work?
Created: 1 month ago
A
24 days
B
12 days
C
36 days
D
15 days
Question: Musa can do 1/4 of a work in 6 days. In how many days will he complete the work?
Solution:
Musa can do 1/4 of a work in 6 days.
∴ He will complete the work in = 6 × 4 = 24 days
∴ Musa will complete the work in 24 days.
0
Updated: 1 month 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: 1 month 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: 1 month ago
