instruction:
In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
question:
Problem: if a and b are the roots of the equation x 2 - 9 x + 20 = 0 , find the value of a 2 + b 2 + ab ? 
Options: a ) 57 , b ) 59 , c ) 61 , d ) 63 , e ) 65
answer:
c


question:
Problem: for any positive integer n , the sum of the first n positive integers equals n ( n + 1 ) / 2 . what is the sum of all the integers between 1 and 50 ? 
Options: a ) 1275 , b ) 1542 , c ) 985 , d ) 1024 , e ) 1125
answer:
a


question:
Problem: 500 x 223 + 500 x 77 = ? 
Options: a ) 2736900 , b ) 2738800 , c ) 150000 , d ) 2716740 , e ) none of them
answer:

c