12:15 - 1+1 = 2
12:30 - 2 + 2 = 4
12:45 - 4 + 4 = 8
1 - 8 +8 = 16
1:15.......
.......
3 - 4096
Number of toothpicks required per student = At least 9
Total number of students = 30
Number of toothpicks required for the entire class = At least 9 × 30 = At least 270
Number of toothpicks in the bag in the class storage room = 50
Additional number of toothpicks required to be bought to make sure there are enough toothpicks = 270 - 50 = 220
Hence, she needs to buy 220 toothpicks.
Mean: ( 9 + 7 + 6.5 + 7.5 + 7 + 8 + 5 + 6 + 7.5 + 8 ) : 10 = 7.15
Variance:
(Sigma)² = ( 1.85² + 0.15² + 0.65² + 0.35² + 0.15² + 0.85² + 2.15² + 1.15² + 0.35² + 0.85² ) : 10 ≈ 1.15
Answer: C ) 1.15
its is not a repeating decimal and it is a rational number because a rational number is a number that does not have repeating decimal but a irrational number does have repeating decimal
