Answer : The substances half life in days is, 5.6 days.
Step-by-step explanation :
Half life : It is defined as the amount of time taken by a radioactive material to decay to half of its original value.
All radioactive decays follow first order kinetics.
The relation between the half-life and rate constant is:

where,
k = rate constant = 0.1235 per days
= half-life
Now put all the given values in the above formula, we get:


Thus, the substances half life in days is, 5.6 days.
Answer:
x=13
Step-by-step explanation:
Q is the midpoint of PR
PQ + QR = PR
PQ= QR
PQ+QR = PR
QF + QR = PR
2QR = PR
2*43 = 9x-31
86 = 9x-31
Add 31 to each side
86+31 = 9x-31+31
117 = 9x
Divide each side by 9
117/9 = 9x/9
13 =x
Again
1000kg = 1ton
3000kg = 3 tons