The first equation is 
(Equation 1)
The second equation is
(Equation 2)
Putting the value of x from equation 1 in equation 2.
we get,


by simplifying the given equation,


Using discriminant formula,


Now the formula for solution 'x' of quadratic equation is given by:


Hence, these are the required solutions.
24.9 miles/hour = 24.9/60 miles/minute = .415 miles/minute
<span>distance = speed * time </span>
<span>= .415 * 30 = 12.45 miles</span>
3/8 divided by 4/5 is the same as 3 * 5 / 8 * 4 = 15/32 or 0.46875
Let x be the months and y be the cost.
Rate of increase of commodity A = 6/3 = $2 per month
Equation:
y = 2x + 4500
Rate of increase of commodity B = 2/4 = $0.5 per month
Equation:
y = 0.5x + 5400
Equating the costs,
2x + 4500 = 0.5x + 5400
1.5x = 900
x = 600 months
x = 600 / 12 = 50 years
The answer is 3. Need an explanation