A serving tray made of brass weighs 21 ounces. This brass is an alloy of 70% copper and 30% tin. What is the weight of the copper tray?
2006-10-03 14:32:45 · 8 answers · asked by Nerds Rule! 6 in Science & Mathematics ➔ Mathematics
14.7 ounces
2006-10-03 14:34:10 · answer #1 · answered by Rune 3 · 0⤊ 0⤋
I THINK YOU LEFT OUT A FEW WORDS...
DIDN'T YOU MEAN TO SAY,
"WHAT IS THE WEIGHT OF COPPER
IN THE TRAY?"
If that is what you want to know,
there is 70 percent of copper in 21
ounces of brass.
So 21 (70 / 100 ) = 14.7 ounces of copper
2006-10-03 14:45:08 · answer #2 · answered by zahbudar 6 · 0⤊ 0⤋
1 ounces = 28.3495231 grams
21ounces = ~595gram brass serving tray
Since copper's specific weight =8.93g/cm3
& tin =7.3g/cm3
We will assume the serving tray is one cubic centimeter; therefore, 70% of 595 = 416.5g copper or (0.70 * 21ounces = 14.7ounces of copper)
Best guess- good luck! This should get you started
2006-10-03 14:45:46 · answer #3 · answered by RHJ Cortez 4 · 0⤊ 0⤋
21 ounces x 70% = 21 ounces x 0.7 = 14.7 ounces
2006-10-03 14:35:32 · answer #4 · answered by buaya123 3 · 0⤊ 0⤋
Technically, you have to know if it is 70% copper by mass or volume. If it is 70% by mass, that is easy, 21 x .7
If it is 70% by volume that is more difficult and becomes a chemistry problem
2006-10-03 14:37:28 · answer #5 · answered by Michael W 2 · 0⤊ 0⤋
Simple...21 oz (total weight)
= x oz of Copper + y oz of Tin
Copper weight = 21 * 0.7 = 14.7 oz
2006-10-03 14:38:40 · answer #6 · answered by alrivera_1 4 · 0⤊ 0⤋
i think you'd fing 70% of 21 ounces. I'm not the smartest person in the world, but i am in advanced math at my school. Oh, I'm out for Fall Break! HaHa!!!! (Not meaning to boast...)
2006-10-03 14:37:31 · answer #7 · answered by Anonymous · 0⤊ 0⤋
14.7 oz
2006-10-03 14:42:57 · answer #8 · answered by First L 1 · 0⤊ 0⤋