The price of petrol increased by 25%. In order that expenses on petrol should…
2016
The price of petrol increased by 25%. In order that expenses on petrol should not increase, one must reduce travel by
- A.
25%
- B.
20%
- C.
18%
- D.
15%
Attempted by 66 students.
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Correct answer: B
Let the original price of petrol be P and original travel be T. Original expense = P × T.
After a 25% increase, new price = P + 0.25P = 1.25P.
To keep expense unchanged, new travel must be such that: 1.25P × new travel = P × T.
Solving: new travel = (P × T) / 1.25P = T / 1.25 = 0.8T.
So, travel must be reduced to 80% of original, meaning a 20% reduction.
हिन्दी उत्तर: मान लीजिए पेट्रोल की मूल कीमत P और मूल यात्रा T है। मूल खर्च = P × T।
25% वृद्धि के बाद, नई कीमत = P + 0.25P = 1.25P।
खर्च अपरिवर्तित रखने के लिए, नई यात्रा ऐसी होनी चाहिए कि: 1.25P × नई यात्रा = P × T।
हल करने पर: नई यात्रा = (P × T) / 1.25P = T / 1.25 = 0.8T।
इसलिए, यात्रा को मूल का 80% तक कम करना होगा, जिसका अर्थ है 20% की कटौती।