For this case, the first thing we must do is define a variable.
 We have then:
 x: George Sisler's average
 y: Suzuki's average
 We then have the following equation that models the problem:
 [tex]x = 0.070 + y
[/tex]
 Substituting values we have:
 [tex]x = 0.070 + 0.350
x = 0.420[/tex]
 Answer:
 Sisler's batting average that year was:
 x = 0.420