Gas at end a: pavata = pa ′ va ′ ta ′ ①.

For B-end gas: pbvbtb = Pb'VB'TB' ′ tb ′? ②

From the topic, PA=PB, PA ′ = Pb ′, VA ′ = VB ′, TA=TB.

Derived from Formula ①: Formula ②,

VAVB = TB′TA′

And va: VB = 2: 3, ta ′ = 300+△ t, TB ′ = 300-△ t are substituted into the solution.

△T=60K

So δt =δt = 60.

So the answer is: smaller; 60 .