David wants to buy some erasers and pencils with a sum of money.
If he buys 8 erasers and 6 pencils, he will have $3.50 left. If he buys 28 erasers and no pencils, he will have no money left. Each pencil costs $1.25. How much money does David have?
Let X be the amount of money David starts with.
8 erasers + 6 pencils = X - 3.50
28 erasers = 0.
Each pencil costs $1.25, so 6 pencils at 1.25 each cost 1.25 * 6 = $<<6*1.25=7.50>>7.50
Thus, David has X - 3.50 = 7.50 dollars
David had X = 7.50 + 3.50 = $<<7.5+3.5=11>>11. Answer: \boxed{11}.
Let's assume the cost of each eraser is 'E' and the amount of money David has is 'M'.
From the given information:
1. If David buys 8 erasers and 6 pencils, he will have $3.50 left.
So, the cost of 8 erasers and 6 pencils can be expressed as: 8E + 6 * $1.25 = M - $3.50
2. If David buys 28 erasers and no pencils, he will have no money left.
So, the cost of 28 erasers can be expressed as: 28E = $0
By solving these two equations, we can find the value of 'M'.
Let's start solving:
From equation 2, we have:
28E = $0
Dividing both sides of the equation by 28, we get:
E = $0/28
E = $0
Substituting the value of 'E' in equation 1, we have:
8 * $0 + 6 * $1.25 = M - $3.50
Simplifying the equation, we get:
$0 + $7.50 = M - $3.50
Combining like terms, we have:
$7.50 = M - $3.50
Adding $3.50 to both sides of the equation, we get:
$7.50 + $3.50 = M - $3.50 + $3.50
Simplifying the equation, we get:
$11 = M
Therefore, David has $11.