Answer :
Using simple linear equations, we can calculate that Andy has 3 quarters.
What is a linear equation?
A linear equation is an algebraic equation of the form y=mx+b, where m is the slope and b is the y-intercept, and only a constant and a first-order (linear) component are included. Sometimes, the aforementioned is referred to as a "linear equation of two variables," with y and x serving as the variables.
Let the number of quarters Andy has = x
number of dollars Andy has = 20 - x
value of quarter = 0.25x
value of dollars = 0.5(20 - x)
Total value = $9.25
⇒ 0.25x + 0.5(20 - x) = 9.25
⇒ 0.25x + 10 - 0.5x = 9.25
⇒ - 0.25x = 9.25 - 10
⇒ - 0.25x = - 0.75
⇒ x = 3
Andy has quarter = 3
He has dollars = 20 - 3 = 17
To learn more about linear equations from given link
https://brainly.com/question/2030026
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