A 70 kg metal bar made of alloy of tin and silver lost 7 kg of its weight in the water. 10 kg of tin loses 1.375 kg in the water; 5 kg of silver loses 0.375 kg. What is the ratio of tin to silver in the bar?
Choices:
A) 1/4 B) 2/5 C) 1/2 D) 3/5 E) 2/3
you can simply use this formula to avoid confusion:   w1/w2 = (A2 - Aavg)/(Avg - A1)   Here is how you will find the values of A1 an A2.   We have an overall loss (average loss). The average loss is 7 kg when 70 kg alloy is immersed.   This is a loss of (7/70)*100= 
<gadget id="calculator">(7/70)*100</gadget>
<output>10</output>
10%.   This is Aavg   The loss of tin is 1.375 kg for every 10 kg.   This means it loses   (1.375/10)*100= 
<gadget id="calculator">  (1.375/10)*100</gadget>
<output>13.75</output>
13.75% of its weight in water.   This is A1.   The loss of silver is .375 kg for every 5 kg.   This means it loses   (.375/5)* 100= 
<gadget id="calculator">  (.375/5)* 100</gadget>
<output>7.5</output>
7.5% of its weight in water.   This is A2.   Weight of Tin/Weight of Silver= (Silver's loss - Avg loss)/(Avg loss - Tin's loss)   X/Y = (7.5 - 10)/(10 - 13.75) = 2/3   2/3
<result>E</result>
A 70 kg metal bar made of alloy of tin and silver lost 7 kg of its weight in the water. 10 kg of tin loses 1.375 kg in the water; 5 kg of silver loses 0.375 kg. What is the ratio of tin to silver in the bar?