Each number in the sum is even, so we can remove a factor of 2.
2 + 4 + 6 + 8 + ... + 78 + 80 = 2 (1 + 2 + 3 + 4 + ... + 39 + 40)
Use whatever technique you used in (a) and (b) to compute the sum
1 + 2 + 3 + 4 + ... + 39 + 40
With Gauss's method, for instance, we have
S = 1 + 2 + 3 + ... + 38 + 39 + 40
S = 40 + 39 + 38 + ... + 3 + 2 + 1
2S = (1 + 40) + (2 + 39) + ... + (39 + 2) + (40 + 1) = 40×41
S = 20×21 = 420
Then the sum you want is 2×420 = 840.
Answer:
I'm not able to do it but I can tell you how
Step-by-step explanation:
make the 10a-9 equal 14a-25 solve for that a then use the answer to a to then plug in thst number in all of them and that would be your answer
2/5 are girls, therefore 3/5 are boys
3/5 = 24
1/5 = 24 ÷ 3 = 8
2/5 = 8 x 2 = 16
Altogether = 16 + 24 = 40
24 - 1 6 = 8
There are 40 children altogether
There are 8 more boys than girls.
Answer:
Gradient: m = 3
Step-by-step explanation:
m = change in y/change in x
m = 
m = 
m = 12/4
m = 3
Solutions
<span>Ivy has 4 tiles with pictures of plants and 5 tiles with pictures of animals. Ivy keeps all the tiles on a mat with the pictures hidden and mixes them up. She then turns one tile face up and finds the picture of a plant on it. She removes this tile from the mat and turns another over tile without looking. What is the probability that the second tile that Ivy turns over has a plant on it. To solve the problem the first step is to find out how many tiles are in total. Since one of the plant tiles were removed we have 3 left.
</span>
5 + 3 = 8
Now we find the percent by dividing 3 from 8. The top number is called the NUMERATOR<span> and the bottom number is called the </span>DENOMINATOR<span>.</span>
3 ÷ 8 = 0.375
0.375 x 100 = 37.5
Answer = <span>37.5%
</span>
= (A)
