I don't see the picture man
Answer:
225
Step-by-step explanation:
The sum of this series is given by the formula:
![S_n=\frac{n}{2}[2a+(n-1)d]](https://tex.z-dn.net/?f=S_n%3D%5Cfrac%7Bn%7D%7B2%7D%5B2a%2B%28n-1%29d%5D)
Where
S_n is the sum
a is the first term (we get this by plugging in n = 1 into "2n-1", we have 2(1) - 1 = 1)
n is the number of terms (the sum is defined for n = 1 to n = 15, so 15 terms)
d is the common different (the difference is successive terms. Here, 2nd term would be 2(2) - 1 = 3, and first term was 1, so d = 3 -1 = 2)
<em>plugging in the info, we will get the sum:</em>
<em>
</em>
<em>The sum is 225</em>
Answer:

Step-by-step explanation:
You don't need to memorize all of the square roots. Looking at each square root, find a number close to it that you know -- The square root of five is close to the square root of four, which is 2. The square root of 28 is close to the square root of 25, which is 5. 28 is a slightly bigger than 25, so the square root will be slightly greater than 5.
Answer :
x = 53.85
Step by step explanation:
If 78% of x (some numbers) is equal to 42, then we must set this as an equation to find it.
1) Rewriting 78% as a fraction and considering that when we say 78% of some number (x) we mean a product.
78% = 78/100 ➡️ 78/100x = 42
2) Then we can go on :
100 * 78/100x = 42 * 100
78x = 4200
78x/78 = 4200/78 ➡️ x = 53.85
3) Alternatively, simply dividing 42 by 0.78 (78%) would come to the same result :
42/0.78 = 53.85
Answer:
16 : 23
Step-by-step explanation:
23 is a prime number, so it can't be reduced