Question 196218
the jeweler has 42g of alloy (6 times 7)


if the new alloy is 87% gold, then it is also 13% silver (87+13=100)


let x="amount of added silver"


the original amount of silver plus the added silver equals the new amount
___ (5%)(42) + x = (13%)(42+x)


2.1 + x = 5.46 + .13x


.87x = 3.36


x = 3.86 (approx)