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: walking 7 / 6 of his usual rate , a boy reaches his school 3 min early . find his usual time to reach the school ? 
Options: a ) 21 , b ) 28 , c ) 99 , d ) 77 , e ) 66
a

Problem: the value of a machine depreciates at 20 % per annum . if its present value is rs . 1 , 50,000 , at what price should it be sold after two years such that a profit of rs . 30,000 is made ? 
Options: a ) 328897 , b ) 120000 , c ) 877888 , d ) 277768 , e ) 126000
e

Problem: a car is purchased on hire - purchase . the cash price is $ 22 000 and the terms are a deposit of 10 % of the price , then the balance to be paid off over 60 equal monthly installments . interest is charged at 12 % p . a . what is the monthly installment ? 
Options: a ) $ 503 , b ) $ 504 , c ) $ 515 , d ) $ 528 , e ) $ 537

d