Answer:
D. 1.2
Step-by-step explanation:
The sum of an arithmetic sequence is the product of the average term value and the number of terms.
The average term is often computed by averaging the first and last terms of the sequence. It can also be computed by averaging the middle two terms of the sequence (when there are an even number of terms, as here).
We are given a_13 is 1.9. We know that a_12 is 3.7 less, so is -1.8. Then the average of these two middle terms is ...
... (-1.8 + 1.9)/2 = 0.05
The product of this value and the number of terms (24) is ...
... 24·0.05 = 1.2 . . . . . the sum of 24 terms of the sequence
Answer: Choice D
Explanation:
The increase of 9.8% rounds to 10% when rounding to the nearest ten
An increase of 10% would use the multiplier 1.1
Think of it like saying 1 + 0.10 = 100% + 10%
Similarly, the 5.1% rounds to 5% and an increase of this amount will use the multiplier 1.05
So if we started with 20 items, then 20(1.1)(1.05) is the expression that estimates an increase of 10% followed by an increase of 5%. The order doesn't matter (so you could increase by 5% first, then 10% later).
The area of the triangle is 90 m²
Explanation:
Given that the base of the triangle is 15 m
The altitude of the triangle is 12 m
<u>Area of the triangle:</u>
The area of the triangle can be determined using the formula,
where b is the base and h is the altitude
Thus, we have,
and 
Substituting the values in the above formula, we get,
Multiplying the terms, we get,
Dividing, we get,
Therefore, the area of the triangle is 90 m²
Answer:
3
Step-by-step explanation:
