the average age of students of a class is 15.8 years. the average age of boys in the class is 16.3 years and that of the girls is 15.4 years. the ration of the number of boys to the number of girls in the class is?
Options
A) 2 : 6 B) 2 : 3 C) 4 : 5 D) 2 : 1 E) 2 : 4
<gadget id="calculator">15.8 - 15.4</gadget>
<output>0.4</output>

<gadget id="calculator">16.3 - 15.8</gadget>
<output>0.5</output>

<gadget id="calculator">0.4 / 0.5</gadget>
<output>0.8</output>

<result>C</result>
the average age of students of a class is 15.8 years. the average age of boys in the class is 16.3 years and that of the girls is 15.4 years. the ration of the number of boys to the number of girls in the class is?
divide(subtract(15.8, 15.4), subtract(16.3, 15.8))
"let the ratio be k : 1 . then , k * 16.3 + 1 * 15.4 = ( k + 1 ) * 15.8 = ( 16.3 - 15.8 ) k = ( 15.8 - 15.4 ) = k = 0.4 / 0.5 = 4 / 5 required ratio = 4 / 5 : 1 = 4 : 5 . answer : c"