Answer:
He bought 20 balls
Step-by-step explanation:
Cost of a certain number of golf balls = $20
Let 1 golf ball cost $x
This means number of balls bought = 20 / x
<em>If each ball has costed 20 cents less;</em>
Converting 20 cents to dollars = $0.2
$x - $0.2
<em>he could have bought five more for the same money.</em>
Number of balls = 20/x + 5
Using the formulae;
Cost of 1 ball * Number of balls bought = Amount spent
(x-0.2) (20/x + 5) = 20
Expanding the expression;
x(20/x + 5) - 0.2(20/x + 5) = 20
20 + 5x - 4/x - 1 = 20
19 + 5x - 4/x = 20
5x - 4/x = 1
Multiplying all through by x
5x^2 - 4 = x
5x^2 - x - 4 = 0
(5x + 4)(x - 1) = 0
x = 1 or -4/5
-4/5 is unrealistic hence the correct value is;
x = $1
He bought 20 balls; 20 / x = 20 / 1 = 20