Answer:
21 problems right
Step-by-step explanation:
To find the amount of problems he got right, you would have to multiply the amount of questions with the success rate
Amount of questions = 30
Success rate = 70% or 0.70
Amount of questions right = 30 x 0.70
= 21
He got 21 questions right!
If you have any questions, please let me know in the comments section of this answer! If you could mark this answer as the brainliest, I would gladly appreciate it! :D