Answer:
190 square foot
Step-by-step explanation:
School yard = 950 square foot
20% of school yard for student to start garden
Therefore
20/100 x 950
= 190 square foot
60% of 20 quizzes = 60/100*20 quizzes = 12 quizzes
Amount of quizzes remaining = 50 quizzes - 20 quizzes = 30 quizzes
He passes 80% of those 30 quizzes, so
80/100 * 30 quizzes = 24 quizzes
So, he passed 12 quizzes from the initial bunch and 24 quizzes from the rest, which totals to 12 quizzes + 24 quizzes = 36 quizzes.
Then, you see that he passed 36 quizzes, out of the total 50 quizzes, so the ratio is 36 quizzes / 50 quizzes = 36/50, which when converted as a percentage is 36/50 * 100% = 72%.
Therefore, he passed 72% of the quizzes for the entire year.
I would make a tree because there are not that many possibilities. to get 99 with numbers between 1 and 50 you have 50+49 and 49 and 50 nothing else will work because if one spin is less than 49 say 48 to get 99 you need 51 which is impossible. either you 50 then 49 or you get 49 then 50. the others are a bit harder because you need to find all possible spins that will sum to 52 which is a much larger number.
