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'.

Q: Problem: caleb spends $ 64.50 on 50 hamburgers for the marching band . if single burgers cost $ 1.00 each and double burgers cost $ 1.50 each , how many double burgers did he buy ? 
Options: a ) 29 , b ) 10 , c ) 20 , d ) 40 , e ) 45

A: a
****
Q: Problem: how many 3 - digit numbers are divisible by 6 in all ? 
Options: a ) 149 , b ) 150 , c ) 151 , d ) 166 , e ) none

A: b
****
Q: Problem: if money is invested at r percent interest , compounded annually , the amount of the investment will double in approximately 48 / r years . if pat ' s parents invested $ 5,000 in a long - term bond that pays 8 percent interest , compounded annually , what will be the approximate total amount of the investment 18 years later , when pat is ready for college ? 
Options: a ) $ 20000 , b ) $ 15000 , c ) $ 12000 , d ) $ 10000 , e ) $ 9000

A:
b
****