Answer:
Approximately 9.211 times
Step-by-step explanation:
Given
[tex]x = 7.6 * 10^{-22}s[/tex] --- half life of helium-5
[tex]y = 7 * 10^{-21}s[/tex] --- half life of helium-9
Required
How many times greater is y than x
To do this, we simply divide y by x
[tex]\frac{y}{x} = \frac{7 * 10^{-21}s}{7.6 * 10^{-22}s}[/tex]
[tex]\frac{y}{x} = \frac{7 * 10^{-21}}{7.6 * 10^{-22}}[/tex]
Apply law of indices
[tex]\frac{y}{x} = \frac{7 * 10^{-21--22}}{7.6}[/tex]
[tex]\frac{y}{x} = \frac{7 * 10^{-21+22}}{7.6}[/tex]
[tex]\frac{y}{x} = \frac{7 * 10}{7.6}[/tex]
[tex]\frac{y}{x} = \frac{70}{7.6}[/tex]
[tex]\frac{y}{x} = 9.211[/tex]
