a.) His heart beasts 65 times each minute.
Let's determine how many times will his heart beast in 24 hrs.
[tex]\text{ }\frac{65\text{ beats}}{1\text{ \lparen minute\rparen}}\text{ x }\frac{60\text{ \lparen minutes\rparen }}{1\text{ \lparen hour\rparen}}\text{ x }\frac{24\text{ \lparen hour\rparen}}{1\text{ day}}\text{ }[/tex][tex]\text{ = }\frac{\text{65 x 60 x 24 beats}}{\text{ 1 x 1 x 1 day}}[/tex][tex]\text{ = 93, 600 beats/day}[/tex]Therefore, his hear beats 93,600 beats/day