Answer:
9.2 times greater
Step-by-step explanation:
Given that :
Half life :
Helium - 9 = 7x10^-21 seconds
Helium - 5 = 7.6x10^-22 seconds
To obtain the number of tunes helium - 9 half life is greater than helium - 5 ; we divide the half life of helium-9 by the half life of helium 5
7x10^-21 seconds / 7.6x10^-22 seconds
0.9210526 x 10^(-21 - (-22))
0.9210526 * 10^1
= 0.9210526 * 10
= 9.2105
About 9.2 times greater