Step-by-step explanation:
2 × 10⁸ - 7 × 10⁷
= 200,000,000 - 70,000,000
=130,000,000
= 1.3 × 10⁸
The percentage decrease is I think is 4 didn't get A's. I don't know if it's right.
we have given that 
where 
represents the number of elements in C.
where we have 4 and 6 which have two elements.
so 
Answer:
1. In mathematics and statistics, the arithmetic mean, or simply the mean or the average, is the sum of a collection of numbers divided by the count of numbers in the collection. The collection is often a set of results of an experiment or an observational study, or frequently a set of results from a survey.
2. In statistics and probability theory, a median is a value separating the higher half from the lower half of a data sample, a population, or a probability distribution. For a data set, it may be thought of as "the middle" value.
3. The mode is the value that appears most often in a set of data values. If X is a discrete random variable, the model is the value x at which the probability mass function takes its maximum value. In other words, it is the value that is most likely to be sampled.
4. the set of values that a given function can take as its argument varies.
129 becaue its the same suze as the diamond plate which ='s 90 so if you divide it yiu get 129
