Answer:
Given the equation: 
A quadratic equation is in the form:
where a, b ,c are the coefficient and a≠0 then the solution is given by :
......[1]
On comparing with given equation we get;
a =3 , b = 10
then, substitute these in equation [1] to solve for c;

Simplify:

Also, it is given that the difference of two roots of the given equation is
i.e,

Here,
, ......[2]
.....[3]
then;

simplify:

or

Squaring both sides we get;

Subtract 100 from both sides, we get

Simplify:
-12c = -96
Divide both sides by -12 we get;
c = 8
Substitute the value of c in equation [2] and [3]; to solve 

or
or

Simplify:

Now, to solve for
;

or
or

Simplify:

therefore, the solution for the given equation is:
and -2.
They will be there for 40 minutes because 25+15 is 40
Using the binomial probability relation ; the probability that an head is obtained at least 50 times is 0.0271
<u>Using the binomial probability relation</u> :
- P(x = x) = nCx * p^x * q^(n-x)
- p = probability of success = 0.4
- q = 1 - p = 0.6
- n = number of trials = 100
P(x ≥ 50) = p(x = 50) + p(x = 51) + ...+ p(x = 100)
<u>Using a binomial probability calculator</u> :
P(x ≥ 100) = 0.0271
Therefore, the probability that atleast 50 heads are obtained in the trial is 0.0271
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