Answer:
1:10
Explanation:
Hey there
to solve this problem think 9:20 and 3:50 as ratios. In this problem we will add these too
9:20 + 3:50= 12:70
so, if it is 12:70. in one hour there is 60 and in the 12:70 it 70. so we add one more hour it will be 1:10
= 1:10