Sagot :
[tex]21 \geq x[/tex]
[tex]25 \geq 0.99x + 3.99[/tex]
[tex]25-3.99 \geq 0.99x + 3.99-3.99[/tex] (Subtract 3.99 on both sides)
[tex]21.01/0.99 \geq 0.99x/0.99[/tex] (Divide 0.99 to isolate x)
21.01/ 0.99 is 21.222 bar, so round it to the nearest ones place, which is 21.
[tex]21 \geq x[/tex]
Check:
[tex]0.99(21)+3.99[/tex] (Multiply)
[tex]20.79+3.99[/tex] (Add)
[tex]24.78[/tex], which is $25.
[tex]25 \geq 0.99x + 3.99[/tex]
[tex]25-3.99 \geq 0.99x + 3.99-3.99[/tex] (Subtract 3.99 on both sides)
[tex]21.01/0.99 \geq 0.99x/0.99[/tex] (Divide 0.99 to isolate x)
21.01/ 0.99 is 21.222 bar, so round it to the nearest ones place, which is 21.
[tex]21 \geq x[/tex]
Check:
[tex]0.99(21)+3.99[/tex] (Multiply)
[tex]20.79+3.99[/tex] (Add)
[tex]24.78[/tex], which is $25.
25 ≥ 0.99x + 3.99
Subtract 3.99 to both sides:
21.01 ≥ 0.99x
Divide 0.99 to both sides:
21.22 ≥ x
x ≤ 21.22
So he can buy less than or equal to 21 songs.
Subtract 3.99 to both sides:
21.01 ≥ 0.99x
Divide 0.99 to both sides:
21.22 ≥ x
x ≤ 21.22
So he can buy less than or equal to 21 songs.