Prometheus query with "Changes" function and devide operation

Hello All,

appreciate if anyone helps me to unblock here.

I wanted to display % failure for my metrics for given time . I am using changes function to calculate change for my metric for given time and now i want devision of these counts .
Although these 2 queries are given proper count i am not able to plot desired values
if query1 output is 30 and query2(after /) output is 46 , so my desired output is 30/46 i.e. 0.65 . but i am not able to plot is properly, sometimes it shows even Infinity thought second query output is not zero.

we are using v.7.3.1 Grafana .

please point me which function needs to be used for this panel, currently i am using “Total” in “Calculation” drop down with “Field” as “Numeric Field”

(changes((sum by (operation) (operation_failure_count{operation="aggregate",app_type="$app_type",org="$org"}))[$__interval:]))/(changes((sum by (operation) (operation_total_count{operation="aggregate",app_type="$app_type",org="$org"}))[$__interval:]))

below is screenshot for reference :