In a psychology school the grade of the students is determined by the following method: At the end of the first year the grade equals to twice the age of the student. From then on, the grade is determined by twice the age of the student plus half of his grade from the previous year. If Joey's grade at the end of the first year is 40, what will be his grade at the end of the third year?
Choose the correct choice from the following.
A) 74  B) 75  C) 76  D) 77  E) 78
let the age is 'x' so after 1st yr 2x=40 and x=20   after 2nd year (now age become 21)   2*21+ 20= 
<gadget id="calculator">2*21+ 20</gadget>
<output>62</output>
62 grades   after 3rd year(now age becomes 22)   2*22+31= 
<gadget id="calculator">2*22+31</gadget>
<output>75</output>
75   ANSWER:75
<result>B</result>
In a psychology school the grade of the students is determined by the following method: At the end of the first year the grade equals to twice the age of the student. From then on, the grade is determined by twice the age of the student plus half of his grade from the previous year. If Joey's grade at the end of the first year is 40, what will be his grade at the end of the third year?