Answer:
261 stairs
Step-by-step explanation:
If David trips twice every 9 stairs and he has tripped 58 times. We can multiply 9 by 58.
58*9=522
Since David trips twice in 9 stairs, then to find how many stairs he has climbed we need to divide 522 by 2.
522/2=261
David has climbed 261 stairs.
