In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: a statue is being carved by a sculptor . the original piece of marble weighed 250 kg . in the first week 30 per cent is cut away . in the second week 20 per cent of the remainder is cut away . in the third week the statue is completed when 25 percent of the remainder is cut away . what is the weight of the final statue ?
Options: a ) 105 kg , b ) 145 kg , c ) 165 kg , d ) 115 kg , e ) 100 kg
a

Problem: last year a worker saved 15 % of her annual salary . this year , she made 20 % more money than last year and she saved 25 % of her salary . the amount she saved this year was what percent of the amount she saved last year ?
Options: a ) 120 % , b ) 140 % , c ) 160 % , d ) 180 % , e ) 200 %
e

Problem: the population of a town is 7800 . it decreases annually at the rate of 10 % p . a . what was its population 2 years ago ?
Options: a ) 9600 , b ) 8000 , c ) 8500 , d ) 9500 , e ) 10000
a