Answer:
5 plus 15 is 20 and then subtract 10 it will become 10 then add 20 it became 30 then subtract 15 it will become 15 then add 25 to 15 answer 40
Step-by-step explanation:
the numbers are repeated again and again like we added 5 to 15 we got 20
then later we added 20 to 10 it became 30
