Answer:
Well a number is (x) {unknown}
Its 17 more
So x+17=85
Now solve
subtract 17 on both sides
x=68
So the number is 68
(-1,6)(2,-6)
slope = (-6 - 6) / (2 - (-1) = -12 / 3 = - 4
y = mx + b
slope(m) = -4
(-1,6)...x = -1 and y = 6
sub and find b
6 = -4(-1) + b
6 = 4 + b
6 - 4 = b
2 = b
ur equation is : y = -4x + 2 <== this is one
(-1,6)
y - 6 = -4(x + 1) <== this is one
45% - 144
100% - x
/cross multiply/
45x = 144·100
45x = 14400 |divide both sides by 45
x = 320
Answer: 45% of 320 is 144.
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
