Answer:
Robert would have needed 259 point to increase his average to 211.
Step-by-step explanation:
Averages are described by the following equations:
Initial average:
[tex]\frac{x}{n} = 205[/tex]
[tex]x = 205\cdot n[/tex]
Real average:
[tex]\frac{x+241}{n+1} = 209[/tex]
[tex]x + 241 = 209\cdot n + 209[/tex]
[tex]x = 209\cdot n - 32[/tex]
[tex]205\cdot n = 209\cdot n - 32[/tex]
[tex]4\cdot n = 32[/tex]
[tex]n = 8[/tex]
[tex]x = 205\cdot (8)[/tex]
[tex]x = 1640[/tex]
Expected average:
[tex]\frac{x+y}{n+1} = 211[/tex]
[tex]x + y = 211\cdot n+211[/tex]
[tex]y = 211\cdot n + 211 - x[/tex]
[tex]y = 211\cdot (8) + 211 - 1640[/tex]
[tex]y = 259[/tex]
Robert would have needed 259 point to increase his average to 211.