Three mechanics A, B, and C can manufacture 120 units in 12, 20, and 30 hours respectively. What is the ratio of the time taken by A alone to complete the work to the time taken by all three working together to complete the same work?
A
5 : 2
B
4 : 3
C
3 : 1
D
2 : 1
উত্তরের বিবরণ
Question: Three mechanics A, B, and C can manufacture 120 units in 12, 20, and 30 hours respectively. What is the ratio of the time taken by A alone to complete the work to the time taken by all three working together to complete the same work?
Solution:
(A + B + C) together can do in 1 hour = (1/12) + (1/20) + (1/30)
= (5 + 3 + 2)/60
= 10/60
= 1/6
So, working together they complete the work in 6 hours.
And A alone takes 12 hours.
∴ Ratio of the time taken by A and (A + B + C) =12 : 6 = 2 : 1
0
Updated: 2 months 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 months 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 months 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
A canteen requires 105 kgs of wheat for a week. How many kgs of wheat will it require for 58 days?
Created: 2 months ago
A
840 kgs
B
950 kgs
C
620 kgs
D
870 kgs
Question: A canteen requires 105 kgs of wheat for a week. How many kgs of wheat will it require for 58 days?
Solution:
For 7 days it is required = 105 kgs
∴ For 1 days it is required = (105/7) kgs
∴ For 58 days it is required = (105 × 58)/7 = 870 kgs
∴ 870 kilograms of wheat will be required for 58 days.
0
Updated: 2 months ago
