All you have to do is plug in the given values into the given equation and evaluate.
The expression is,

But we have to analyze the problem carefully. This is a natural phenomenon that can be modelled by a decay function. The reason is that, after every hour we expect the medicine in the blood to keep reducing.
Therefore we use the decay function rather. This is given by,

where,


and

On substitution, we obtain;


Now, we take our calculators and look for the constant

,then type e raised to exponent of -1.4. If you are using a scientific or programmable calculator you will find this constant as a secondary function. Remember it is the base of the Natural logarithm.
If everything goes well, you should obtain;

This implies that,

Therefore after 10 hours 24.66 mg of the medicine will still remain in the system.
No he is wrong because 75% more time would be spent doing homework
If it's in a fraction you want it it's 207/50 irregular
And 4 7/50 as a mixed fraction
0-5 because 25th percentile can also be known as the 1st quartile or the first 25% of it. so since the medium is 8 then it would be the first interval or 0-5.
if i am wrong please let me know.