একটি আয়তাকার জমির প্রস্থ এর দৈর্ঘ্যের তিন-পঞ্চমাংশ ,দৈর্ঘ্য ও প্রস্থ উভয়কে দ্বিগুণ করা হলে, নতুন আয়তক্ষেত্রের ক্ষেত্রফল মূল আয়তক্ষেত্রের ক্ষেত্রফলের কত শতাংশ হবে ?
Created: 4 years ago |
best des
A + B)’s 1 day’s work = 1/18
(B + C)’s 1 day’s work = 1/9
(C + A)’s 1 day’s work = 1/12
On adding all above equations, we get
2 (A + B + C)’s 1 day’s work = 1/18 + 1/9 + 1/12 = {2 + 4 + 3}/{36} = {9}/{36} = {1}/{4}
∴ (A + B + C)’s 1 day’s work = {1}/{8}
Now, B’s 1 day’s work = (A + B + C)’s 1 day’s work – (A + C)’s 1 day’s work
= {1}/{8} - {1}/{12} = {3 - 2}/{24} = {1}/{24}
Hence B alone can do the work in 24 days. So option [B] is correct answer.
(B + C)’s 1 day’s work = 1/9
(C + A)’s 1 day’s work = 1/12
On adding all above equations, we get
2 (A + B + C)’s 1 day’s work = 1/18 + 1/9 + 1/12 = {2 + 4 + 3}/{36} = {9}/{36} = {1}/{4}
∴ (A + B + C)’s 1 day’s work = {1}/{8}
Now, B’s 1 day’s work = (A + B + C)’s 1 day’s work – (A + C)’s 1 day’s work
= {1}/{8} - {1}/{12} = {3 - 2}/{24} = {1}/{24}
Hence B alone can do the work in 24 days. So option [B] is correct answer.
Md Azizur Rahman
Founder of Satt
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