Question 626544
a. {{{ P(X < 630) = P(Z < (630-600)/70) }}}
                  = P(Z < 0.4286)
                  = 66.59%

b. {{{ P(630 < X < 730) = P( (630-600)/70 < Z < (730-600)/70 )}}}
                        = {{{ P( 0.4286 < Z < 1.8571) }}}
                        = 30.25%

c. {{{ P(600 < X < 700) = P( (600-600)/70 < Z < (700-600)/70 )}}}
                        = {{{ P( 0 < Z < 1.4286) }}}
                        = 42.34%