A jeweler has 5 rings, each weighing 14 g, made of an alloy of 15% silver and 85% gold. She decides to melt down the rings and add enough silver to reduce the gold content to 70%. How much silver should she add?

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.

emily solved for a part when she should have solved for the whole. 875,000 should be the numerator of the equivalent ratio. 70 x 12,500 is 875,000. so the answer is 100 x 12,500 which is 1,250,000.

2b2t

explanation:

2b2t