Yes ABD=CBD since they both are just half of the triangle
25% 6 divided by 24 will give you the percentage of copper in the bar
7 <span> more than 3 times a number </span>
<span>more than is code for + </span>
<span>times is multiply </span>
<span>so 7+3n=31 </span>
<span>solve: </span>
<span>3n=24 </span>
<span>n= 8</span>