You should definitely ask your parents or teacher. Also, never give up :)
Trust me just keep trying your best and don't tell yourself that you can't do it :)
<span>Equation:
silver + silver = silver
0.45x + 0.60(40-x) = 0.48*40
----------------
45x + 60*40 - 60x = 48*40
--------
-15x = -12*40
x = (4/5)40
x = 32 lbs (amt of 45% slloy needed)
40-x = 8 lbs (amt of 60% alloy needed)</span>
Well u do 31.2 x 18 which is 561.6 then u divide by 2 because the formula for a triangle is base x height divided by 2 so It is 280.8