Question 1168139
mean=total/n
so n*mean=total
the total was 6* mean for each after 6 days.
on the 7th day 7*meanA for warmer and 7*meanB for cooler=total
we know mean A-0.5=mean B
Change over 7 days means a 3.5 degree drop for mean B

example 60/60/60/60/60/60/60=total 420 and mean of 60 after 6 days and after 7 days
60/60/60/60/60/60/x. Here the average has to be 59.5 so the total will be 416.5.  That means the temperature on the last day has to be 56.5

3.5 degrees