Answer:
10.98 days is 10.98/3.66 = 3 half life periods and half of the mass is lost at each half life. You can do this in your head. I have!!
Step-by-step explanation:
Answer:
10.D
Step-by-step explanation:
A=2(wl+hl+hw)
Step-by-step explanation:
Circumference of a circle is 2piR
C=2piR and R=10
C=2(3.14)(10)
So the circumference is 62.8 cm
Answer:
20kg of 25% copper alloy
30kg of 60% copper alloy
Step-by-step explanation:
There are 2 kinds of metal, first metal(A) have 25% copper while the second metal(B) has 60% copper. The metalworker want to create 50kg of metal, which means the total weight of both metals is 50kg (A+B = 50). The metalworker also want the metal made of a 46% which is 23kg(0.25A + 0.6B = 0.46*50). From these sentences, we can derive 2 equations. We can solve this with substitution.
A+B = 50
A= 50-B
Let's put the first equation into the second.
0.25A + 0.6B = 0.46 *50
0.25(50-B) + 0.6B =23
12.5 - 0.25B + 0.6B =23
0.35B=23 -12.5
B= 10.5/ 0.35= 30
Then we can solve A
A= 50-B
A= 50-30
A=20
Answer:
A
Step-by-step explanation:
12/4=3
20/4=5
