A mixture of 750 kg of alloy of copper and tin contains 25% tin. How much tin must be added so that it becomes 70% of the mixture?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 1125 kg.
Given:
Weight of mixture = 750 kg
Amount of tin in the mixture = 25%
Explanation:
Quantity of tin in alloy of 750 kg = 25% of 750
⇒ 25(750)/100 = 187.5 kg
Let the required quantity of tin to be added be x kg.
New weight of tin = (187.5 + x)kg
New weight of alloy = 750 + x
Percentage of tin in new alloy = [(187.5 + x)/(750 + x)] × 100% = 70%
According to the question -
⇒ [(187.5 + x)/(750 + x)] × 100 = 70
⇒ (18750 + 100x) = (52500 + 70x)
⇒ 30x = 33750
⇒ x = 33750/30 = 1125 kg