Size of the transferred file = transfer time · transfer rate. Note that the file size in the second case is 4/6 = 2/3 times smaller than the file size in the first case. Since the file transfer rate is the same, the time it takes to transfer a 4MB file over the same connection is also 2/3 times less. It will be equal to 2/3 * 180 = 120 seconds.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.