The task is to generate the correct answer for a given math problem.

Problem: if a = 105 and a ^ 3 = 21 × 25 × 45 × z , what is the value of z ?
49

Problem: the population of a bacteria culture doubles every 2 minutes . approximately how many minutes will it take for the population to grow from 1,000 to 300,000 bacteria
16

Problem: if the price of 357 apples is rs . 1517.25 , what will be the approximate price of 49 dozens of such apples ?

rs . 2500