SATHEE: Quantitative Aptitude Ques 231

Quantitative Aptitude Ques 231

Question: An alloy of steel contains iron and carbon in the ratio 3: 4. If 120 kg of iron is added to the alloy, then the same ratio become 5: 4. Find the initial quantity of iron in the alloy.

Options:

A) 175 kg

B) 180 kg

C) 160 kg

D) 185 kg

Show Answer

Answer:

Correct Answer: B

Solution:

Given, $ \frac{Iron,\text{(}l\text{)}}{Carbon,\text{(}C\text{)}}=\frac{3}{4} $

$ \Rightarrow $ $ 4\times l=3C $
$ \Rightarrow $ $ C=\frac{4l}{3} $ (i) and $ \frac{l+120}{C}=\frac{5}{4} $
$ \Rightarrow $ $ \frac{l+120}{\frac{4l}{3}}=\frac{5}{4} $ [from Eq.(i)]

$ \Rightarrow $ $ \frac{3,(l+120)}{4l}=\frac{5}{4} $
$ \Rightarrow $ $ \frac{3,(l+120)}{l}=\frac{5}{1} $

$ \Rightarrow $ $ 3l+360=5l $
$ \Rightarrow $ $ 5l-3l=360 $

$ \Rightarrow $ $ 2l=360 $
$ \Rightarrow $ $ l=\frac{360}{2}=180 $ Hence, initial quantity of iron in the alloy is 180 kg.

Quantitative Aptitude Ques 230

Quantitative Aptitude Ques 232

Quantitative Aptitude Ques 231

Question: An alloy of steel contains iron and carbon in the ratio 3: 4. If 120 kg of iron is added to the alloy, then the same ratio become 5: 4. Find the initial quantity of iron in the alloy.

Options:

Answer:

Solution:

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