Answer:
17.7
Step-by-step explanation:

Answer:
14.99 hours
Step-by-step explanation:
The formula for half-life is given as,
R/R' = 2ᵃ/ᵇ...................... Equation 1
Where R= Original mass of sodium-24, R' = mass of Sodium-24 after disintegration, a = Total time taken for sodium-24 to disintegrate, b = half-life of sodiun-24.
Given: R = 1 kg, R' = 0.0156 kg, a = 90 hours
Substitute into equation 1 and solve for b
1/(0.0156) = 2⁹⁰/ᵇ
Taking the log of both side
log[1/(0.0156)] = log(2⁹⁰/ᵇ)
log[1/(0.0156)] = 90/b(log2)
90/b = log[1/(0.0156)]/log2
90/b = 6.0023
b = 90/6.0023
b = 14.99 hours
b = 14.99 hours.
Hence the half-life of Sodium-24 is 14.99 hours
15+22(4+11)=x
4+11=15
22*15=330
15+330=345
x=345
Answer:
x = 6
Step-by-step explanation:
Given
- 5.2x + 57.9 = 15.9 + 1.8x ( subtract 1.8x from both sides )
- 7x + 57.9 = 15.9 ( subtract 57.9 from both sides )
- 7x = - 42 ( divide both sides by - 7 )
x = 6
Answer:
I think its D.
Step-by-step explanation: